(Solved) Business rule not working (notify account manager)

Hello,

I have a business rule set up to notify the account manager by certain events. The rule has been set up and the 'perform this acount' option is: Notify Account Manager by Email.

For testing purposes I have selected multiple account managers there, but none of these persons receive the mail.

If I look into the issue which should send the mail, it is saying:

Created by System

Business Rule Failed Backup naar Koen applied

So that tells me that the Business Rule is applied, but no mail is send out. See screenshot below about the action.

Any idea what could be wrong?

Kind regards,

Jarry