Even with perfect settings, the "pipeline" between you and the server can be blocked. IMAP email broke Outlook, can't get it working again
The most frequent reason IMAP fails is a breakdown in "trust" between your client and the server. why-won-t-imap-work
IMAP requires three specific "keys" to open the door: the server address, the port number, and the encryption type. Even with perfect settings, the "pipeline" between you
Repeated failed attempts can trigger a temporary IP block or account lockout from the provider's side to prevent brute-force attacks. 2. Structural Configuration Errors Repeated failed attempts can trigger a temporary IP
For many services, IMAP access is turned off by default for security. You must manually enable it within the webmail settings of your account (e.g., Gmail Settings > Forwarding and POP/IMAP). 3. Network and Software Interference
Many providers (like Gmail and Yahoo ) now require OAuth2 or Two-Factor Authentication (2FA) . If you have 2FA enabled, your standard password will no longer work for IMAP; you must generate a unique App Password through your provider's security portal.
Standard IMAP typically uses port 993 for secure SSL/TLS connections or port 143 for non-secure connections. Using the wrong port—or the wrong encryption method for a specific port—will result in a "Connection Refused" error.