On a fresh install of owncloud I came across a problem – trying to share a file to someone over email came up with the following error:

“Error mail Invalid address: August 17, 2012, 13:44”

My first check was to see if there was actually a mail client installed. There wasn’t, so I installed sendmail. However, I was still getting the same error. Checking the mail error logs I saw that the host name was not the same as the domain for the email. I changed the host name to something meaningful using the command:

“hostname domain.name” replacing domain.name with the required name.

Still, I was receiving the error. This was solved by also changing the line “DAEMON_OPTIONS(`Port=smtp,Addr=0.0.0.0, Name=MTA’)” adding the 0.0.0.0 myself.

Owncloud now sends files by email without error.