Provider guides
Zoho Mail SMTP and IMAP Settings for Cold Email
Zoho Mail server settings for connecting a mailbox over SMTP/IMAP, plus what Zoho’s published sending policy means for cold outreach.
5 free checks per day · 20 with a free account
DKIM Checker
Look up a DKIM selector and see its TXT or CNAME record.
Common selectors:
A selector that isn't found doesn't prove DKIM is missing — your provider may use a different selector. Check a sent message's DKIM-Signature header for s=.
Finding your selector
Google Workspace usually uses google; Microsoft 365 uses selector1 and selector2. Other providers show the selector in their DNS setup screen.
The quickest way: open the headers of an email you sent and read the s= value in the DKIM-Signature line.
Error code guides
Common errors and how to fix them
All DNS error codesResources
Related guides
Quick reads to help you plan audiences, sending volume, sequences and measurement before launch.
Provider guides
Yandex Mail SMTP and IMAP Settings for Cold Email
Yandex Mail server settings for connecting a mailbox over SMTP/IMAP, app passwords, and Yandex’s published recipient limits.
Deliverability
SPF, DKIM and DMARC for Cold Email
A practical explanation of the three core email authentication mechanisms and how they work together.
From checks to campaigns