Hi Sanjana
If that is the case, then PFUD/user compare will resolve for you. It also means that you did not describe your scenario accurately as that suggests you made changes to the user access (and possibly change of date format was a coincidence).
If fixing the SU56 error does not resolve your error, you will unlikely get much more assistance from this space without posting an extract of your code. Otherwise, it's a guess game - particularly when it is custom development.
Regards
Colleen