Sometimes the company file doesn't appear in The Order Exchange in the Accounting System window. There can be a few reasons for that.
1. Make sure that the API is installed and running. For SE(Server edition), the client edition should not be installed and running. Check the bottom right corner of your system to make sure its not running.
Then make sure that the API for the SE is installed.
It will be installed in the path (C:\Program Files (x86)\MYOB\API\2.0.2021.4)
2. MYOB has to be open in the same system as The Order Exchange, for it to locate the company file.
Open the company file in MYOB and then open TOE to located the company file.