See the question and my original answer on StackOverflow

AxMSTSCLib corresponds to this Remote Desktop ActiveX control, located in in \windows\system32\mstscax.dll.

This "Microsoft RDP Client Control" (that's its display name) serves many versions of the main class called RdpClient, currently from 1 to 13.

0x80040111 error, aka CLASS_E_CLASSNOTAVAILABLE means the code is asking for a version of RdpClient that's not available on the PC it currently runs.

It's a setup deployment/issue, i.e. the program was developed on a PC that has a higher version than the program it runs. You can review your .cs files or your form.designer.cs, check for code like new AxMSTSCLib.AxMsRdpClient11() and try a lower version like AxMsRdpClient9, etc.