5.7.0 Bug report: (1) Can't create full rig due to server error. (2) Assembled MH can't move skeleton in sequencer

Summary

I created two cinematic short films in Unreal Engine 5.6.1, handling everything from start to finish. The projects involved five Metahumans and numerous props across different scenes, and the entire process went smoothly without major complications.
However, a couple of weeks ago version 5.7 was released, and I decided to give it a try. Since then, I’ve been struggling just to create a single Metahuman. Attempts to generate a full rig repeatedly fail due to server errors.
The Developer Assistant has been helpful - each time a rig fails, it suggests new solutions. A few days ago, I managed to assemble two Metahumans, but when I tried animating them in Sequencer, only the control rig gizmos moved while the bodies remained static. At that point, the Assistant’s suggestions were beyond what I’ve learned so far.
Today, I successfully assembled one Metahuman, but with the exact same settings, the second MH rig failed again with the “server error”. After wasting nearly two weeks, I’ve decided to stop experimenting with 5.7 and return to 5.6.

Please select what you are reporting on:

Creative

What Type of Bug are you experiencing?

Character

Steps to Reproduce

Create a new Metahuman and attempt to create full rig.

Expected Result

Auto rigging face and body mesh should be completed successfully.

Observed Result

Turned on all plugins, amended DefaultMutable.ini as suggested by Dev Assistant, occasionally the rig completes successfully but most of the time with same settings, attempts fail due to “server error”.

Platform(s)

Unreal Engine 5.7.0., MS Windows 11