Workbench hangs while logging in to AEM Forms server

When a user tries to connect Workbench to AEM Forms server, the Workbench hangs. The workbench also hangs regularly after a few minutes of usage.  

The issue can occur if a port used in a workbench process is blocked, multiple endpoints across all applications are configured to use this same port, or an antivirus, malware, and firewall blocks a port.  

Free the port to and restart Workbench.