As part of Salesforce Summer '26 security enhancements, we have implemented additional security measures in the Mass Assign Permissions app, including support for PKCE (Proof Key for Code Exchange) in the OAuth authorization flow. Due to these security updates, users may be required to re-authorize the application and may see the Authorize button again on the Mass Assign Permissions tab. This is expected behavior and helps ensure secure access between Salesforce and the connected system. Once authorization is completed successfully, you can continue using the application as usual.