IMAP is generally a protocol that help to read messages from your Gmail in other mail clients for example outlook apple mail much more. If you are receive Gmail IMAP not working
error then you can follow these 6 solutions that fix your imap.gmail.com is not Responding on iPhone/iPad issue.
1. Allowing access into your google account
2. You must check your internet connection
3. Deleting the email account and adding it again
4. Update your Operating System/email client
5. force quitting the application
6. Emailing your own account.
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