Аttach file to email error 503

[alexisc]

External files are not attached, this is a problem for all users.
Error 503.
The log file is empty.
Tell me how to fix it.

[Maximus]

Hello,
this error was thrown by your server. Error 503 means "service unavailable". Check its error log file to define a problem.
If you are using a host, then contact a support service.

[alexisc]

thanks for the answer.
Logs are unfortunately empty, there are no entries for this error, everything works on the hosting side.