Use script to install plugin via Install Plugin Script Step.
You may get error 1551 for failure.
We have no idea what caused error 1551!
Get(LastExternalErrorDetail) is empty and no messages from FileMaker except about it failed.
Expected Result: When error occurs, please always put error message into LastExternalErrorDetail property, so we can query with Get(LastExternalErrorDetail)
Actual Result: No clue on what is going on.