I am currently fighting with a Versalink B405DN
I'm not the IT guy at work, I'm just security but our position backfilled IT and so the employees keep coming to me to solve things. So far this one has been beyond me.
We found out the main cause of a scan to email issue was an email account password change, when that was corrected it started throwing 016-764 errors.
In connections with all the settings as they currently are, testing the connection comes back as working. Actually attempting to scan to email however gets the fault code every time and I am at a loss for what needs to be changed to fix it.
Google and youtube have both been extremely unhelpful
I found another post with the same FC listed that may help you here:
If that doesn't help, please contact the Support Department. Support options for your device are listed HERE.