SAML Shibboleth stop working after some days - Unsupported Request


I’ve configured SSO/SAML app with Shibboleth but, after everal days of woring properly, when user tries to Login, they get the message: Web Login Service - Unsupported Request

If I delete the configuration and reload it again, it will work for some days but after, mesage reapers again.

Does anybody using Shibboleth faced the same problem?