How to Warm Up Lark Mail with IMAP, DKIM and a Safe Ramp

Warm up Lark Mail for at least 14 days on an existing domain, or 3–4 weeks on a new domain, before outbound. If you skip IMAP/SMTP access, the mail-client password or DKIM, sending may work while replies and spam recovery fail. This guide gives the setup, ports, DNS checks and daily ramp.

Lark gets less coverage than Gmail and Microsoft 365, but the rules are the same: authenticate the domain, connect the mailbox correctly, then raise volume slowly. If you want the engine to handle daily sending and reply handling, keep BobWork’s Lark Mail warm-up guide open while you connect.

You should still understand the setup. Lark and Feishu tenants can use different hosts. Admins may also block third-party mail clients. A mailbox can look healthy in the Lark web app and still fail through IMAP.

Use this Lark Mail warm up plan

Start with the mailbox, not the campaign. A warm-up plan only helps if the domain passes SPF, DKIM and DMARC, and the mailbox can send and receive through authenticated mail-client access.

Use this schedule for a real outbound mailbox. It is conservative enough to protect a new sender, but not so slow that you waste a month on an existing domain.

BobWork Email Warm-up starts at 3 emails per day, adds 2 per day, and caps at 30 per day by default. The cap is editable per mailbox, up to 100, but most outreach mailboxes do not need that. Weekends run at 30% volume.

Do not treat warm-up volume as permission to blast. Warm-up creates normal mailbox activity. It does not make a weak offer, scraped list or broken DNS safe.

For outreach capacity, add mailboxes before you force one mailbox to carry all volume. A few stable mailboxes at modest volume usually age better than one mailbox sending hard all day.

What must be enabled first?

Confirm that your Lark or Feishu admin allows IMAP and SMTP. This is the step most teams miss.

In the admin console, go to the mail administration area and look for third-party client access. The exact labels vary by tenant. Search for “IMAP”, “SMTP” or “third-party client” if the menu has changed.

The admin should allow mail-client access for the user or user group that owns the mailbox. If the organisation disables it, no warm-up tool can connect through IMAP, even if the password is correct.

Next, check DNS. Lark Mail can host the mailbox, but your domain still needs the usual authentication records.

Do not copy SPF or DKIM values from another domain. Lark can change the required value by region or tenant. Use the record shown in your own admin console.

For DMARC, a monitoring policy is enough at the start. Many teams start with p=none, then move to stricter policies after they confirm SPF and DKIM alignment. The key is having a valid record and watching failures.

BobWork checks SPF, DKIM and DMARC daily per domain. It looks for common DKIM selectors, including lark and feishu, and shows the domain state inside the warm-up account. You can also use the free SPF checker, DKIM checker and DMARC checker before connecting.

How do you create credentials?

Lark Mail usually does not work like a basic username-and-password mailbox when third-party clients are involved. You normally need a mail-client password created inside the account.

Use the mailbox that will send outreach. Open Lark or Feishu, go to account settings, then mail settings, then third-party mail client or client password settings. Generate a new mail-client password.

Copy it once and store it in your password manager. If you lose it, create a new one rather than guessing.

Use this password only for IMAP and SMTP. Your normal Lark login password, SSO password or workspace password is not the right credential for most mail-client connections.

If your tenant uses two-factor authentication or enterprise SSO, the mail-client password is even more important. It gives the mail client a scoped credential without exposing the main login.

Use the full email address as the username. For example, use alex@example.com, not alex. Mail servers often host many domains behind one endpoint, so the local part alone may fail.

Before you connect a warm-up tool, test the credential in a standard mail client if possible. Add the account as IMAP, send one message, receive one message, then remove it. This isolates Lark credential problems from warm-up configuration problems.

Lark publishes mail-client and admin guidance in its Lark Help Center. Feishu tenants should also check the current regional documentation in the Feishu Help Center, because hostnames and labels can differ.

Which hosts and ports work?

Lark global tenants and Feishu tenants can use different mail hosts. Use the hosts shown in your own mailbox settings or admin console. Your tenant setting is the source of truth.

For IMAP, use port 993 with SSL/TLS. For SMTP, use the secure port shown by Lark or Feishu. The common value is 465 with SSL/TLS.

If your tool offers STARTTLS on 587, do not guess. Use the port and encryption mode Lark shows for your tenant. Port and encryption mismatches often produce vague login errors.

Also check the sender identity. The SMTP username and visible From address should be the same mailbox unless Lark has explicitly allowed aliases. Sending as an alias before DKIM and DMARC alignment is correct can create avoidable failures.

If you use a custom tracking domain for campaigns, do not add it during the first warm-up days. First confirm that normal one-to-one mail lands well. Then add campaign infrastructure and test again.

How should warm-up run?

Connect your Lark mailbox. One is enough in the shared network; if you switch the account to Private pool, only your own mailboxes write to each other and you need at least two.

The private-pool option is useful for Lark teams with internal test domains, regional domains or multiple product mailboxes that do not want strangers’ mailboxes exchanging mail with theirs.

Once connected, the free pool handles the repetitive parts automatically: sending, replies, spam rescue and DNS checks. BobWork sends plain text office-style messages with no links and no images. About 40% of received warm-up mail gets a reply, and threads end after 3 messages.

The timing should look normal, not theatrical. BobWork spreads sends across 09:00–18:00 in each mailbox’s own time zone, checks every 15 minutes with randomness, and prevents a pair from writing to each other twice within 3 hours. Peers on a different domain or provider are picked twice as often.

Do not add sales links to warm-up mail. Warm-up messages should not promote your product, use campaign copy or include tracking pixels. They exist to create normal mailbox behaviour and measure placement.

If you are warming manually, follow the same idea. Send short plain text notes. Reply to some. Archive some. Move any false spam placements back to the inbox. Do not send the same sentence between every mailbox.

A warm-up tool can do this more consistently than a person. It also avoids the usual manual mistake: sending ten test messages in five minutes, then doing nothing for two days.

For a day-by-day view, use the email warm-up schedule. If this is your first mailbox, read what to expect during first-time warm-up before judging the first few spam landings.

What should you monitor?

Do not rely on “sent” status. A message can be accepted by the receiving server and still land in spam.

Check both authentication and placement:

BobWork’s spam rate is the share of a sender’s warm-up mail that receiving mailboxes found in Spam over 7 days. That is different from a seed-list estimate. It is measured directly inside receiving inboxes.

The health score is 0–100. Healthy is 85 or above. Watch is 60–84. At risk is below 60. Blocked means the login or permission failed.

The “ready for outbound” state requires three things: 14 or more days warming, a 7-day spam rate of 3% or lower, and at least 30 warm-up emails received.

For major consumer inboxes, sender reputation also depends on complaints and authentication. Google’s sender guidance says to keep spam complaint rates below 0.1% and avoid ever reaching 0.3%. Read Google’s current rules in the Email sender guidelines. Yahoo publishes similar guidance in its sender best practices.

Those rules apply even when your mailbox is hosted on Lark. The receiving provider judges the sender domain, mailbox behaviour, content and recipient reaction.

If your domain is new, be patient. A new domain with perfect DNS can still lack history. Use 3–4 weeks, keep real outreach small, and avoid sudden list uploads.

If you need the wider diagnosis, use why emails go to spam and the new-domain spam guide.

How do you fix failures?

Most Lark warm-up issues are setup issues, not reputation issues. Fix the connection before you interpret placement data.

Use this checklist when a mailbox fails, sends slowly or lands in spam early.

If the mailbox connects but does not send, check SMTP separately. Some admins allow IMAP read access but restrict SMTP submission.

If receiving works but spam rescue does not, check IMAP folder names and permissions. Warm-up tools need to see the spam folder to move their own warm-up mail back to the inbox.

BobWork only touches mail carrying its own hidden header. For Zoho API senders it can also use a known subject, but Lark uses the IMAP route. Real mail is never read, moved or answered.

If authentication passes but DKIM fails at receivers, the DNS record may not have propagated. Wait, then query the selector again. Also check that you did not publish the DKIM record under the wrong domain, such as the root when Lark asked for a selector host.

If everything is technically correct and spam remains high, stop adding volume. Review your sending list, copy, links and domain age. Warm-up cannot compensate for poor targeting or complaint-heavy campaigns.

When should outreach start?

Begin outbound only after the mailbox has stable history. For BobWork, that means 14 or more days warming, a 7-day spam rate at or below 3%, and at least 30 warm-up emails received.

Start with your safest prospects. Send plain text. Avoid heavy HTML, link-heavy templates and attachments in the first campaign. Keep the first replies human and quick.

Continue warming during campaigns at 10–15 per day. Do not stop warm-up the day outreach begins. You want ongoing positive interactions, especially if real recipients reply slowly.

If you need more capacity, add another Lark mailbox. Do not push one mailbox from 40 real emails to 150 because the first week looked fine. Reputation damage often appears after the first batch of negative signals, not immediately.

BobWork Email Warm-up is free, needs no credit card, and supports up to 20 mailboxes per account. For Lark Mail, connect with IMAP and a mail-client password. By default the mailbox warms in the shared network; switch the account to Private pool and only your own mailboxes write to each other. If you also use Gmail, Zoho, Yahoo, iCloud, Amazon SES, SendGrid, Mailgun or other IMAP/SMTP mailboxes, they can join the same account. Outlook and Microsoft 365 are not supported yet.

Frequently asked questions