My friend tries downloading Simbrief flightplan in the FMS. It is downloaded and visible in the tablet, but importing it via the ACARS - Request Simbrief results in

a scratchpad message "error downloading data". He follows exact the same steps I did. I do not have this problem.

What could be cause and solution of this problem?

All of the times I have seen it on the forum here, it is due to the name not entered correctly. Tell him to double check that he entered the "Simbrief Alias" in the field on the EFB