If you see an error next to your mailbox, you likely haven't enabled the required settings for your mailbox.

Refer to this article to enable SMTP for Microsoft Office 365 email.

Refer to this article to enable IMAP for your Gmail account.

Refer to this article to enable IMAP & SMTP for your Zoho mail account.

Refer to this article to enable IMAP & SMTP for Hostinger mailbox.

Refer to mailbox provider documentation to enable IMAP and SMTP for the mailbox.
Note some providers may allow such configurations only with a paid license.

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