If it isn't the printers hostname then it must be the SMTP server hostname, check that it is valid, and if it is, look to your time(has to be within 3 minutes) and DNS (Try 8.8.8.8) or switch the ther SMTP servers IP address instead.
I have tried that and it doesn't seem to fix the problem. it's still giving me an error "invalid hostname" . thanks
By setting the hostname to something valid in the DNS settings, same will go for domain name (use WORKGROUP.local if you don't have one)
I have been normally using the email function to scan documents to myself, but recently it hasn't been working. When I try to email the scanned document to myself it is giving me an error stating "invalid hostname". How can I go about resolving this issue? Thanks