FBA login not working after creating search service application

[TezzChaudhary]

I have migrated from SharePoint 2013 to SharePoint 2019, and system was working fine, FBA is also working..But today when I created Search Service application, suddenly I am seeing, FBA is not letting me logged in.. While creating search service application, I used existing app pool name, is it may be the issue... Please suggest as I am in deep trouble..

[#2]

What do you mean used an existing app pool? Since Web Applications and Service Applications don't share IIS Application Pools, that should be a non-issue -- it's also recommended to use a single App Pool for all Service Apps, SSA included.

Do you have error messages? ULS? IIS log? App Event Log?