I see this is a common problem. I have been through the forum pages and don't seem to be able to find a solution.
The 6515 is brand new out of a box, so not sure if it needs a firmware update. Again, cant seem to find a way to do this - if needed please advise on this too.
Any help greatfully received!
Google Admin to show Less Secure Apps enabled.
Make sure the right network is set as primary (Wired or Wireless, which can only be done inside the Wired, even if Wired isnt plugged in)
EWS > Connectivity > Ethernet > Common > Edit
When typing the password into the fields, make sure you are not using Chrome or EDGE. They corrupt the password fields. Safari/Internet Explorer are fine, Firefox as well
If using 2 factor auth on the account, you will need to create an App Password for the device since it clearly can't get or respond to the text/email it uses.
And firmware is almost certainly needed, and linked in probably every single scan thread