Hi there, Pauliej. 

One reason that you're prompted with this error could be your Database Server Manager status has stopped. The status should remain Running to avoid it. Though your users are switching company files to the other, it shouldn't cause the error. 

Refer to the Solution 2: Check hosting and services in this article that will walk you through how to enable hosting on the server. 

The Community is always around to help you with your questions.