Lark Mail Emails Going to Spam: DNS, Volume and Warm-Up Fixes

Fix Lark Mail emails going to spam by proving three things first: SPF, DKIM and DMARC pass and align, then sending volume stays human. If you skip either side, Gmail and Yahoo can keep filtering even clean-looking messages. Use the tables below to diagnose the failure, repair DNS, reduce risk and verify recovery.

If you need connection steps, use the Lark Mail warm-up guide. For automated reputation building, BobWork Email Warm-up supports Lark Mail through IMAP and SMTP with a mail-client password.

Diagnose Lark Mail spam first

Start with the symptom. Do not edit random DNS records or increase warm-up volume until you know which failure you are fixing.

One symptom can have more than one cause. A new Lark domain with correct DNS still needs a ramp. A broken DKIM record needs DNS repair, not more warm-up. A scraped list needs list repair.

Which numbers matter?

Use thresholds to decide whether the problem is authentication, reputation or volume. Do not increase volume while delivery is unstable.

Google documents authentication, complaint and unsubscribe expectations in Google’s email sender guidelines. Yahoo publishes similar requirements in Yahoo sender best practices.

Fix DNS in order

Authentication is the first fix because it is binary. The receiver can verify your domain, or it cannot. Work through SPF, DKIM and DMARC before changing copy or warm-up settings.

Confirm SPF

SPF says which servers may send for your domain. In Lark admin, open your domain setup and copy the SPF value shown there. Publish it as a TXT record on the root domain.

The host is usually @ or the bare domain, depending on your DNS provider. The value must start with:

v=spf1

If Lark is your only sender, the record should include Lark’s current sending source as shown in Lark. Do not guess the include value from an old guide. Provider values can change.

You must have one SPF TXT record, not two. This is wrong:

v=spf1 include:provider-a.example ~all

v=spf1 include:provider-b.example ~all

Receivers can treat multiple SPF records as a permanent error. Merge approved senders into one record.

Use the free SPF checker after publishing. SPF also has a 10-DNS-lookup limit under RFC 7208. If you use Lark plus campaign tools, check the lookup count before adding more includes.

Confirm DKIM

DKIM signs mail with a private key in Lark and a public key in DNS. Receivers compare both. If they match, DKIM passes.

In Lark, open the email domain authentication area. Copy the DKIM record exactly. The host will be a selector under _domainkey, commonly with a Lark or Feishu selector. The value is domain-specific, so never reuse another domain’s key.

A DKIM host follows this pattern:

selector._domainkey.yourdomain.com

The TXT value starts with:

v=DKIM1; k=rsa; p=

Some DNS providers want only the host part before the domain. For example, they may want selector._domainkey, not selector._domainkey.yourdomain.com. If DKIM fails after publishing, check this first.

Use the free DKIM checker. BobWork’s domain check also looks daily for common selectors, including lark and feishu, then shows DKIM status per domain.

Add DMARC

DMARC tells receivers what to do when SPF and DKIM do not align with your visible From domain. Start with monitoring, not rejection.

Create a TXT record at:

_dmarc.yourdomain.com

Use this starter value:

v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com; adkim=r; aspf=r

Use a real mailbox for reports. If you do not want reports, you can omit rua, but monitoring helps during a fix.

DMARC alignment is defined in RFC 7489. For a practical setup flow, use the free DMARC checker and this SPF, DKIM and DMARC guide.

Do not jump to p=reject while you are still fixing mail flow. Move to stricter policies only after normal business mail and campaign mail pass consistently.

Align the sending source

Authentication can pass but still fail alignment. Alignment means the domain in the visible From address matches, or is related to, the domain authenticated by SPF or DKIM.

For example, you send from:

alex@yourdomain.com

But the Return-Path uses another sender’s domain, or DKIM signs with a tool vendor’s domain. SPF or DKIM may pass for that vendor, but DMARC can still fail for your domain.

Keep the Lark setup simple while fixing spam placement:

• send normal mailbox traffic through Lark Mail
• avoid multiple SMTP relays during diagnosis
• remove unused senders from SPF
• check every campaign tool that sends as your domain
• make sure the From domain is the domain you authenticated

If you use a cold email tool, confirm whether it sends through your Lark SMTP account or through its own infrastructure. Those are different reputation paths.

Open a delivered test message in Gmail and choose Show original. Look for:

• SPF: PASS
• DKIM: PASS
• DMARC: PASS
• mailed-by: your domain or an expected sending domain
• signed-by: your domain or an aligned subdomain

If DKIM passes for your domain, DMARC usually has a clean path. If only SPF passes, forwarding and relays can still break SPF later.

Reduce volume and risky copy

Once DNS is correct, volume is the next lever. Spam filters react badly to sudden jumps, especially from a new domain.

For cold outreach, a typical safe range is 30–50 real cold emails per day per mailbox after warm-up. New domains should move slower. If you need more volume, add mailboxes and domains instead of pushing one mailbox harder.

For larger sending setups, a common layout is 2–5 mailboxes per sending domain. That keeps each mailbox human-sized and gives you room to pause one address without stopping every campaign.

Follow these rules while fixing delivery:

• pause sends to unverified or old lists
• stop any campaign with high bounces
• send only during working hours
• avoid large same-minute batches
• remove contacts who do not match your offer
• honour unsubscribes quickly
• keep follow-ups relevant and limited

Mailbox providers do not only judge authentication. They watch whether recipients open, reply, ignore, delete, mark spam or unsubscribe. A technically valid email can still be unwanted.

If you are not sure how much to send, use this guide on cold emails per day per mailbox. Keep the fix conservative until inbox placement stabilises.

Content rarely fixes a broken domain by itself. Still, risky content can push a borderline sender into spam.

Start with the first email. It carries the most filtering risk because there is no thread history yet.

Make these changes:

• send plain text while diagnosing
• remove images and attachments
• use one link at most, or no links
• remove link tracking until placement improves
• avoid URL shorteners
• use a normal signature
• write to a specific person
• make the reason for contact clear
• include a simple opt-out line for outreach

For bulk or cold email, one-click unsubscribe matters. Google and Yahoo expect easy unsubscribe for bulk senders. Yahoo says bulk senders should honour unsubscribes within 2 days.

Do not hide the unsubscribe option. If people cannot opt out, more of them mark spam. Complaints are worse than unsubscribes.

Your copy should look like an office note, not a flyer. If your message has five claims, three links and a calendar button, simplify it before testing again.

A short sequence is usually enough. If you need a structure, use this 4-step cold email sequence template and stop on reply, bounce or unsubscribe.

Use warm-up only when ready

Warm-up helps when the mailbox is technically correct but has little or uneven sending history. It creates gradual mailbox activity before and during campaigns.

Warm-up is a fit when:

• SPF, DKIM and DMARC pass
• the Lark mailbox is new
• the domain is new or quiet
• you plan to start cold outreach
• volume has been inconsistent
• spam placement is mild, not total
• you can wait 7–21 days

Warm-up is not the fix when:

• DKIM fails
• DMARC fails because of alignment
• Lark account sending is blocked
• your list is scraped or invalid
• bounce rate is high
• recipients complain
• the content looks deceptive
• your domain is already on a major blocklist

In BobWork Email Warm-up, Lark connects through IMAP and SMTP with a mail-client password. The free warm-up does the ramp automatically: it starts at 3 emails per day, adds 2 per day, and caps at 30 per day unless you edit the mailbox cap. Weekends run at 30%.

The tool uses a shared warm-up network by default, or a private pool per account if you prefer. A private pool needs at least two mailboxes. The engine only touches its own warm-up mail, identified by its hidden header. Real mail is never read, moved or answered.

For a new domain, warm for 2–3 weeks before serious outreach. For an existing domain with correct DNS, 7 days is a reasonable minimum. Keep warm-up running at 10–15 per day during campaigns.

BobWork marks a mailbox ready for outbound after 7+ days warming, a 7-day spam rate of 10% or less, and at least 30 warm-up emails received. Treat that as a floor, not permission to double volume immediately.

Do this now

Work in this order. Fast checks come first. Slow reputation fixes come later.

Do not skip to step 10 if steps 2–5 fail. Warm-up cannot authenticate your domain.

If several Lark mailboxes on the same domain are affected, fix DNS once at domain level. Then test each mailbox separately. A domain problem hits every mailbox. A mailbox problem usually follows one address, one campaign or one sending tool.

After the fix, send fresh tests to Gmail, Yahoo, iCloud and a business mailbox you control. Open the headers. SPF, DKIM and DMARC should pass. The visible From domain should align with at least one authenticated domain.

Then watch real replies. If people reply normally, that is a stronger signal than a test inbox. If tests improve but real prospects ignore or complain, targeting still needs work.

Review the next 7 days for these signs:

• fewer messages in spam
• no authentication failures in headers
• no bounce spike
• no sudden sending blocks
• stable opens and replies where you can measure them
• complaint rates below provider thresholds
• warm-up spam rate trending down

If you use Google Postmaster Tools, keep the spam complaint rate under 0.1% and never above 0.3%. Yahoo states a spam-rate threshold under 0.3%. Microsoft publishes authentication requirements for high-volume Outlook.com senders, but a numeric complaint threshold is not stated.

If delivery improves, hold the new sending pattern for several days. Increase gradually only if replies, bounces and complaints stay healthy.

If nothing changes after DNS passes and volume is reduced, isolate the cause. Send the same plain-text message from another domain. Send a different message from the same mailbox. Test a small, verified recipient group. Separate domain reputation, mailbox reputation, content and list quality.

When the mailbox is ready, keep warm-up active at a low level during outreach. BobWork Email Warm-up is free for up to 10 mailboxes, with no credit card and no time limit. For Lark Mail, connect with IMAP and SMTP using a mail-client password, then watch domain checks, spam rate and ready status before sending more cold email.

Frequently asked questions