Error with Data Base Config, After Upgradation,

[munnangi ramanjaneyareddy]

We have Upgraded JIRA Server Instance from 8.5.19 to 9.4.5,
Upgradation Successful But Unable to Connect With Database,
I took Data Folder, dbconfig, Server, setenv Files and Replaced after Upgradation, But Same Error we are getting,

Kindly Help Us,

[Nic Brough -Adaptavist-]

Welcome to the Atlassian Community!

I assume you used the binary installer to do the upgrade (as the instructions for that tell you to do some saving of files before proceeding). 

My best guess is that you misunderstood why you need to take copies of the files.  You are not supposed to simply destroy the new versions that the upgrade created, you keep them so you can understand what changes you should merge into the new ones.  You certainly do not replace the upgraded data directory with the old one - the upgrade will have changed some stuff, and putting back the old one will render some of the files unusable in the new version.

You may be able to rescue this, but I would keep hold of the backups of the install and data directories you took before you tried to upgrade, as well as the database backup.

Start with a look in the application log, that should give you more information on the exact problem, and check the compatibility of your database version with 8.5 and 9.4, as well as the database driver.