Symptom

When accessing OnTime for Microsoft with domain(SSO) login enabled the server reports “HttpStatus Code 400 Bad Request – RequestUrl/Field to Long” during the domain logon redirect on the OnTime Server the C:\Windows\System32\LogFiles\HTTPERR\httperr1.log shows
2015-12-10 12:51:43 10.41.32.152 62489 10.41.40.35 80 HTTP/1.1
GET /ontime/auth.html?redirect=http://ch-s-0008355:8080/ontimegcms/ 400 - RequestLength -

Fix

1. Using regedit add the following values HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\HTTP\Parameters Key,
   DWORD(Decimal value)
MaxFieldLength 65534
MaxRequestBytes 65534
MaxTokenSize 65535
2. Stop the OnTimeMSAuth NT Service
3. Restart the HTTP service From an elevated command prompt
   >net stop http
   >net start http
4. Start the OnTimeMSAuth NT Service.