Error code: SEC_ERROR_REUSED_ISSUER_AND_SERIAL

UCS - Univention Corporate Server
3

The SEC_ERROR_REUSED_ISSUER_AND_SERIAL error in Firefox indicates that there’s an SSL certificate problem due to the reuse of a certificate’s issuer and serial number. This typically happens when a server presents a certificate that has the same issuer and serial number as a previously used certificate. This can cause confusion and security issues because certificates should be unique.

Steps to resolve the issue:-

  1. Check Certificate Validity
  2. Update the Server Certificate
  3. Clear Browser Cache
  4. Update Server Software
  5. Check your router

The sec_error_reused_issuer_and_serial error in Firefox mainly occurs because of duplicate security certificates in use.