Send result to canonical address

[motofzr1000]

I'm trying to send my form results to an email address, which appears to be a canonical address. When clicking the submit button, I get an error message saying 'Could not instantiate mail function'.

I've also tried sending the results to a working email address on which I've received form results, and have set up a mail forwarder on this address, but that doesn't seem to work neither.

Any suggestions how to solve this?