Password expiration in Frontend Portal

Currently:

The HR Manager's password expires every 90 days and always needs to be reset manually by Security Team in ISS. The manager is supposed to be able to reset the password themself as it requests their old password and what the new password they want it to be.

But when the manager tries to reset it, there is an error and the security team again needs to reset the password in the backend of SAP ECC5.0.

Can you please suggest any way, maybe parameter change to be set for this users such as the manager to successfully change their passwords, rather than security team to do it for them?