Don't know exactly how your config looks like, but there are 3 things to check for scan to mail...
- the mail address used for authentication
- the mail address used to send the mail
- the mail address that is to be shown as the sender (aka the 'reply-to' address)
some mail servers/relays are more or less flexible regarding the matching of these 3... the first thing to test is definitely to have all 3 identical, and then to play around to see what your server/relay allows..
Regards
Philippe