Mozilla VPN is currently experiencing an outage. Our team is actively working to resolve the issue. Please check the status page for real-time updates. Thank you for your patience.

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

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

Thunderbird 128.2.3esr (64-bit) Sending of username did not succeed. Mail server responded: invalid command

  • Nuɖoɖo aɖeke o
  • 0 masɔmasɔ sia le wosi
more options

Hi your all,

I have used Thurderbird more than 6 years and it was really good for me without any complaints. However, I updated the email from Supernova to Nebular (128.2.3esr (64-bit) yesterday and I got the following message and I cannot receive any emails now. Fortunately, sending is no problem.

"Sending of username did not succeed. Mail server pop3.mailplug.co.kr responded: invalid command"

I searched the previous similar issues in the forum and I checked my status. However my own was the right one that people recommend.

Receiving Server: pop3.mailplug.co.kr / Port: 995 / SSL/TLS / Normal password Sending Server: smtp.mailplug.co.kr / Port: 465 / SSL/TLS / Normal password

Actually, I am using several pop email apps but I have no any issues on those apps except for the Thunderbird. The problem is Thunderbird is my main app. I am alternatively using outlook but really want to return to Thunderbird. Could you anyone help me out?

Thank you for your kindness in advance!

Hi your all, I have used Thurderbird more than 6 years and it was really good for me without any complaints. However, I updated the email from Supernova to Nebular (128.2.3esr (64-bit) yesterday and I got the following message and I cannot receive any emails now. Fortunately, sending is no problem. "Sending of username did not succeed. Mail server pop3.mailplug.co.kr responded: invalid command" I searched the previous similar issues in the forum and I checked my status. However my own was the right one that people recommend. Receiving Server: pop3.mailplug.co.kr / Port: 995 / SSL/TLS / Normal password Sending Server: smtp.mailplug.co.kr / Port: 465 / SSL/TLS / Normal password Actually, I am using several pop email apps but I have no any issues on those apps except for the Thunderbird. The problem is Thunderbird is my main app. I am alternatively using outlook but really want to return to Thunderbird. Could you anyone help me out? Thank you for your kindness in advance!

You must log in to your account to reply to posts. Please start a new question, if you do not have an account yet.