iCloud not accepting my passcode

Today I had to reset my iPhone since there was some issues after iOS 14.3 update. Now while restoring my iPhone from backup it asks for old passcode that was used previously in the iPhone. But when I enter the passcode it says "Verification failed". I could not understand why it is happening when I have already entered the correct passcode which I used very frequently before reset (face mask does not allow unlocking iPhone).

Any solution for this. I cannot restore my backup and they are very important.