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I can't send mail through Thunderbird for my POP.Gmail account

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I can no longer send mail from my Thunderbird POP.Gmail account. When I try to do so I instantaneously get an Alert with the following message: “An error occurred while sending mail: The mail server sent an incorrect greeting: +OK Gpop ready for requests from [my IP address] ]k16mb102005795ool”. (The numbers following my IP address always vary). I can receive email at this address, but I can send nothing. I have several more email addresses on Thunderbird (all through Gmail) and they work fine but they are all IMAP. My POP incoming port is 995 and the SMPT output port is 465. My ISP is Spectrum. Can someone please help?

I can no longer send mail from my Thunderbird POP.Gmail account. When I try to do so I instantaneously get an Alert with the following message: “An error occurred while sending mail: The mail server sent an incorrect greeting: +OK Gpop ready for requests from [my IP address] ]k16mb102005795ool”. (The numbers following my IP address always vary). I can receive email at this address, but I can send nothing. I have several more email addresses on Thunderbird (all through Gmail) and they work fine but they are all IMAP. My POP incoming port is 995 and the SMPT output port is 465. My ISP is Spectrum. Can someone please help?

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Cookies must be accepted in TB Options/Privacy & Security for OAuth to complete. Remove the passwords in Saved Passwords in Privacy & Security, restart TB, enter the new password in the OAuth window when asked.

If you have multiple gmail accounts, make sure each one is sending on a gmail smtp whose User Name matches the User Name for the sending account. Right-click the account in the Folder Pane, Settings, check Outgoing Server (SMTP) in the right pane. Edit SMTP server... to see the User Name.

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All Replies (6)

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What's the authentication on the incoming and outgoing servers? It should be OAuth2. 'Incorrect greeting' usually means the authentication method or password is wrong. Also, disable the VPN if you have one.

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I switched the authorization from Normal Password to OAuth2 on both the account and the outgoing server and tried to send a test message. Got exactly the same error message. I changed my password yesterday as well as uninstalling NordVPN. No help. Interestingly however if I log into my account directly with Gmail, I have no problem sending so I think the problem must be with Thunderbird.

Sincere thanks for your help.

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Seçilmiş Həll

Cookies must be accepted in TB Options/Privacy & Security for OAuth to complete. Remove the passwords in Saved Passwords in Privacy & Security, restart TB, enter the new password in the OAuth window when asked.

If you have multiple gmail accounts, make sure each one is sending on a gmail smtp whose User Name matches the User Name for the sending account. Right-click the account in the Folder Pane, Settings, check Outgoing Server (SMTP) in the right pane. Edit SMTP server... to see the User Name.

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Thank you so very much for all your help. the key was your instruction to examine the outgoing SMTP server for each of my email addresses. When I went to examine the outgoing server for my POP account, I saw to my horror that it was set to use Port 995. I immediately changed the port to 465 and voila! - problem solved! I reset all my email accounts back to "Normal Password" from OAuth2 and now everything works as normally as before. I didn't have to delete and reset my passwords or choose new passwords.

I can't thank you enough for your invaluable advice and for the time you spent helping me. I wish I could repay you somehow.

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You may find that OAuth2 is less trouble than 'normal password', as OAuth2 isn't affected if Google automatically turns off access for 'less-secure apps' or if two-step verification is applied to the account. OAuth2 will likely be mandatory in the near future anyway.

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Thank you for the information. You have been invaluable.