mail does contain a valid email address and there have been no configuration changes since it was working last.
I tried resetting the password and resyncing several times as well.
still no... 
Single ldap user = Authentication rejected
Try to logon to Active Directory from Shell using ldapsearch.
ldapsearch -x -D "<user>@ads.domain.tld" -b "ou=<ou containing that user>,dc=ads,dc=domains,dc=tld" -H ldap://<AD server name>.ads.domain.tld:389/ -W sAMAccountName=<user>
Test for both, the bind user and the user not working. Both should give back the same result.
Example:
https://community.grommunio.com/d/1558-active-directory-ldap-sync-with-starttls-not-working/4
- Edited
typo disregard
I get a complete result for both
Strange! Try deleting the user in Grommunio Admin and resync / Import User.
Delete or detach? zi don't see a delete option?
Go to Users and click the red bin icon on the right side next to that user. Just confirm deletion, do not check anything. Now re-import it and try to login again.
- Edited
I'm starting to feel pretty dumb today.... There are no red trash cans in the user menu!?!?
nevermind - had top use a bigger screen....
it's not finding the deleted user user when I resync...
- Edited
I tried deleting a second user and now sync says 0/1 sync'd. 1 error.
Sync is ignoring 2 users now.
no errors show under journalctl -f
no German Umlaut in password.
This is an appliance install
Reboot and sync = 1 sync'd successfully
import added bad the users deleted
login still fails
I'm only trying the grommunio web at the moment
Both users that I deleted and restored cannot login
It's always dns.... I don't know the exact solution yet, but the issue is related to AD logon restrictions and dns. Thank you to everyone who tried to help. Now that I am logged back in, all the mail for the users I deleted and resync'd is missing. Any ideas why? TY
Keeebs Both users that I deleted and restored cannot login
you have to do some shenanigans in those scenarios. or how di you du that exactly?
https://docs.grommunio.com/man/gromox-mbop.8.html