Domain Login Not Working
Entry in our faq 2 if you are having problems with all services at your domain then work through the following checklist of common issues.
Domain login not working. Login with local account to do the below checks. The upn suffix is used only within the active directory forest and it is not required to be a valid dns domain name. Check the dns configuration should have a working primary dns server. The other domain group was not working could not connect to the server at all.
If your website is not working but your emails are check the why is my website not working. Has your domain expired. Able to ping the dns server. Not even directly granting the connect sql server level permission worked.
Able to nslookup or resolve with primary dns. Domains that have not been renewed will be suspended by the registry. Just to note that we only have one domain but many upn suffix.