Hi All, 

           I have got an issue while starting the User Profile Syn Service. I just Upgraded the Sql Version from Sql 2012 to SQL 2014 sp1 and i checked it was working fine. After I delete the existence User Profile Service Application (for migrating Profile DB) and recreate a new Service Application i got an issue of start User Syn service. Both FIM service can start manually without an issue. but UPS only not start and I found the following error message in ULS log. Pls help.

UserProfileApplication.SynchronizeMIIS: Failed to configure MIIS post database, will attempt during next rerun. Exception: System.Configuration.ConfigurationErrorsException: ERR_CONFIG_DB

What is the your SharePoint 2013 build?

You need to have at least April 2014 Cumulative Update if you have SQL 2014.

https://support.microsoft.com/en-us/kb/2760265

Issue that this hotfix package fixes

If you have Microsoft SQL Server 2014, you cannot run profile synchronization in SharePoint Server 2013 SP1 by using the Forefront Identity Management engine

HI mani,this issue is due to many reasons like DB,Permissions,Apppool.please check the link that provides more information on the issue and the solution.

http://expertsharepoint.blogspot.de/2014/03/user-profile-synchronization-service.html