API application could not connect to server. 

Error message from log file

...

Could not connect to SystemWeaver server!
SystemWeaver.ClientAPI.SWIOError: Error reading buffer: “Systemite.Lz4.Lz4” S

ystem.TypeInitializationException: “Systemite.Lz4.Lz4” 

System.IO.FileNotFoundException: Unable to load lz4 compression library

...

Resolution

Confirm that the server OS, the Visual C++ Redistributable for Visual Studio and the API application are all either 32 or 64 bit. A mismatch could be causing the problem. If the C++ Redistributable is missing, you will need to install it: 

Download Microsoft Visual C++ Redistributable for Visual Studio 2017. 

You may also need to have the vcruntime140.dll (also in the correct 32 or 64 bit version) in the same location.