Login hangs on "Finishing up..." when using AIM v4.0.972 on Mac OS 9.2.1

[D3CL4NZ]

Subject of the Issue

When attempting to sign-in to the server using AIM version 4.0.972 on Mac OS 9.2.1, the login hangs on "Finishing up...". The authentication completes successfully (I set the logging to trace and I see the authentication complete), but it's unable to complete whatever happens in that "Finishing up..." step.

Deployment Environment

• Retro AIM Server Version: v0.9.0
• Installation Method: Pre-built
• Client(s) Used: AIM v4.0.972 on Mac OS 9.2.1
• Other Relevant Details: The AIM client is modified to connect to my AIM server. I used ResEdit to change the resource that stores the server URL. When I set this to iwarg.ddns.net, it works fine, so I know it's not an issue with my modification method.

Steps to Reproduce

1. Use ResEdit to change the "AIM Server" inside the STR# resource bundle to the address of the Retro AIM Server.
2. Set the port to 5190.
3. Attempt to sign-in.

Expected Behavior

The sign-in will complete and I will be presented with the Buddy List.

Actual Behavior

The sign-in progress hangs on "Finishing up..."

Troubleshooting Data

[D3CL4NZ]

Note: If you want to test this for yourself, but don't have a computer with OS 9, you can use the SheepShaver emulator.