combing two reports

I combined two power bi in this manner-

kept one report(report1) as is, connected it with another(report2) report's live connection dataset. then I added blank pages into report1 copied report2's content to report1 blank pages. created necessary relationships. and I could see the data successfully in the pages which I copied from report2 to report1.

Problem-

report1 previously existing pages now give error,

The relationship didn't give any error before I connected report2's live dataset to it.

This is the first time I have encountered an error like this in power bi. I would appreciate any help, thanks