Temporary lookup failure

[kotan]

When sending a letter via Thunderbird, an error often pops up:
The mail server replied: "Temporary lookup failure".
Happens after the fifth attempt only it turns out to send the letter. The problem has been around for about a year or two.

[Ayespy]

@kotan This does not appear to be related in any way to Vivaldi Mail. Can you clarify why you posted it here?

[kotan]

@Ayespy I am using Vivaldi Mail via Thunderbird. What is not clear here?
Vivaldi Mail smtp server intermittently responds with "Temporary lookup failure".

[Ayespy]

@kotan You are using Vivaldi Webmail. This is a Webmail query. I will move it to the appropriate category. (Vivaldi Mail is the built-in mail client in Vivaldi and is unrelated to your Vivaldi webmail account. Obviously, you can't use a Vivaldi browser feature via Thunderbird.)