Avatar for Username

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

This thread was archived. Please ask a new question if you need help.

Authentication Failed, must login..

orlandot
orlandot
more options

I am unable to send emails. I keep receiving this failed message " 5.7.1 [R8] Authentication Failed, must login.." I contacted my cable provider and they are at a loss. I have tried everything but with no luck. My operating system is Microsoft 10. Hope you can help.

I am unable to send emails. I keep receiving this failed message " 5.7.1 [R8] Authentication Failed, must login.." I contacted my cable provider and they are at a loss. I have tried everything but with no luck. My operating system is Microsoft 10. Hope you can help.

All Replies (1)

user01229325
user01229325
more options

Post your Thunderbird troubleshooting info. From the Help Menu select Troubleshooting Information. Copy to Clipboard Come back here and paste into a reply window