Corrupted attachment with CEM (PEC)

Dear all,
i configured the accout of my CEM (PEC) in my eM Client with the setting suggested by my CEM provider, but when I download messages with attachments (.pdf,.zip, etc.), the attachment are corrupted.

If i check the same emails in the webmail of the CEM provider or using a different email client, for example Thunderbird, I’m able to download attachment correctly.

Do you have some suggestions to fix this issue?
My eM Client version is 8.0.3385, free edition

Regards,
Stefano