Hi Brent,

I have error log which might be the main reason behind it.

You have a uniqueness constraint violation. This would have come from your original application having runtime constraints set, not database. 

The solution is to take a branch from your last commit before the upgrade to database uniqueness was enabled. This may be before you moved to Mendix 9. In this branch you put the migration toolkit that you get from Mendix Support (you need to email them and specifically ask for the uniqueness migration toolkit). Once installed you can clean up the data to remove any duplicates you may have. Once this is cleaned, you should be able to deploy your Mendix 9 application.

More details on this can be found here.
https://docs.mendix.com/refguide7/uniqueness-constraint-migration/

Good luck!

Plz refer to the snapshot below :

Ok, I can’t make out the full error there, but from what I can see it looks to be that an association was one type (e.g. 1 to many) and then it was changed to another (1 to 1).

I’d try changing the association in question from whatever it is to a different multiplicity (e.g. 1 to many).

Hope that works.

It could be a double entry in the database, have you just restored a database from prod/acc? maybe delete that database and restore it again.

else try to open the app in the older version or branch and you should analyze the association type.