An update of WHMCS's OpenSRS gateway module is available for download to accommodate for immediate service-level changes provided by OpenSRS.
On Monday at 10:30pm EST, OpenSRS reset the passwords associated with reseller domains. This change rendered all domain management, for existing domains, non-functional in the OpenSRS module provided by WHMCS.
In response to this, the WHMCS development team has updated the OpenSRS module to use an alternative authentication method which removes the reliance on the reseller web interface domain passwords.
This module is compatible with both WHMCS v5.3.x* and v6.0. Once you deploy this updated module, all OpenSRS functionality will be restored.