one of our server we installed the 10.21 and it was working fine but we downgrade that to 10.10.1 it get failed and we did this for test case to raise change when I downgrade its failed to communicate with URL after that I directly moved to 10.13 again it failed after that I have moved to 10.14 it failed now I have agin installed the 10.21 but still I am getting this error.now how i can fix this or how i can revert this with 10.21 ?
@Durgule As @iJake asks, do you have a backup of your MySQL database from before you 1st installed JSS 10.21? You really should restore it along with the version of the JSS you started with, then consult the Installing Java and MySQL for Jamf Pro 10.14.0 or Later document on the Java requirements for different JSS versions. In short, JSS 10.13.0 and earlier require Java 8, while JSS 10.14.0 and later require Java 11.
You also need to look at the Incremental Upgrade Scenarios for Jamf Pro 10.0.0 or Later guide as you cannot upgrade directly from JSS 10.10.x to 10.21
Did you blow away the database before restoring? If not, there will be tables from the 10.21 JSS that didn't exist in the older versions, and those can interfere with startup.
I ran into this issue with a rolled-back upgrade when I tried to upgrade again. The JSS was trying to convert a table during startup, but that table already existed from the prior failed upgrade attempt, and I had to drop it so the upgrade could proceed. The JSS log should have better error messages that can help.