ERROR emails

Is there anyone who can tell me what I should do…?

I have installed this, but I keep receiving ERROR emails all the time and I can’t stop them!
In less than 10 minutes I’ve received several emails saying:

This message has been sent from http://agency.112-danmark.dk. You can disable or control who receives them by changing the Postie “Notify on Error” setting.

File is empty. Please upload something more substantial. This error could also be caused by uploads being disabled in your php.ini file or by post_max_size being defined as smaller than upload_max_filesize in php.ini.

Is there anyone who can help me with this?

Look at this (currently 337 emails just from the system):
http://agency.112-danmark.dk/wp-content/uploads/2026/01/Skaermbillede-2026-01-13-154316.png