Invalid preceding regular expression regex pattern

Tried adding several regex patterns like **(?=.*[a-z])(?=.*[A-Z])(?=.*[0-9])(?=.*[!@\\$%\\^&\\*])(?=.{8,})**
**(?=.*\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[@$%&*]).{8,}** etc but getting fatal error
Found that issue is caused when used **?** after **(**
Can someone help?

Reproduce the fatal error with the regular expression patterns shown in the issue, then inspect the repository's pattern-validation and matching entry points. Confirm which syntax is rejected and document or test the expected handling of these patterns; the issue is done when the behavior is covered and the failure is resolved or clearly reported.

Written by the indexing model from the issue text.