Are you using a 64 bit FME server?
In that case it would require the 64 bit ESRI geoprocessing DLL's on the server to be installed.
What I'm meaning is that the service called "FME Server Engines" won't be able to access network resources if it runs as "Local System", like this:
If you need FME Server to access network resources, you'll have to reconfigure the Engine service to run as a domain user with specific right on that network share, as in the link I posted below.
Thanks for your response.
It is running as a user of the FME server, not my local account, if that is what you mean.
Which user is your FME Server Engines service running as?If it's running as Local System, you cannot access network resources and you'll have to configure it to run as a domain user.
See here for more information:https://docs.safe.com/fme/html/FME_Server_Documentation/Content/AdminGuide/Running_FME_Server_Engines_Under_Different_Account.htm