Another case of Outlook not working for a user on Exchange 2013.
I opened RPC Client Access log on Exchange server under C:Program FilesMicrosoftExchange ServerV15LoggingRPC Client Access . And searched for the user. And I found this: 2014-11-05T14:33:23.233Z,386250,,/o=Customer/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=Example.nly,,OUTLOOK.EXE,15.0.4659.1000,Cached
I stumbled over the name, as it looked like the “cn=Example.nly” missed one character. I would think it should be Example.Only and not Example.nly. Opened the user in ECP, and as I thought.
The Exchange alias name contained Ö which seems to be a invalid character in Exchange. But ECP did not complain on this.
After we changed Ö to O, but the user was still not able to log on to Outlook.
I checked the attributes and saw that LegacyExchangeDN also need adjustment /o=Customer/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=Example.nly. After changing this and wait some time for everything to replicate, the user was able to use Outlook.
NB! When changing LegacyExchangeDN remember that this will cause NDR when internal people uses autocomplete from Outlook. I recommend converting the old LegacyDN to X500 address.