Did you check the Generate Log File from Document Properties Like below?
Check this box and save it and try reloading on QMC, once you get the error it will generate log file. Log files are located at QDS logs folder.
Which data source you are connecting to ? If using ODBC does the relevant ODBC driver is added to your DSN on the Server?
You can enable the generate log file information as mentioned in the screenshot above to generate the log file, from the log file you can able to find what exactly the issue is.
Most probably the issue will be the access to the data source. Normally people while doing development and testing
they do reload from their local, they point their data source to local folders. After migrating to production they may miss out to change the source path.
Or you can also check the database connection string what you are using in the desktop set up is same in server. Make sure you are able to access the source database from the server.