A year or two ago I used to be able to create custom connectors that connected to an on-premise api service. I did this by both a blank connector and an OpenAPI file.
Today I've tried to create a new custom connector using the same methods and I am now presented with a "Start New Trial" error.
The licence I have is called Microsoft 365 A5 for Faculty, and this used to work. I am now not sure what licence is required and any advise would be greatly appreciated.