You could try setting
rpc_log=some_file.txt rpc_log_full=trueunder the `[C]` section and check the log file if it contains some useful information.
This is very very useless. If the project is open, I can't open this file. Windows simply tells me Access Denied. If I close the project, this file will also gone.
Also, did you use an absolute path under Project->Properties->Base Path? This should point to the root directory of your project.
The default value is absolute path and I have never touched it.
What happens when you run `clangd` from the console? (It should block until you press Ctrl+C after which it should quit)
I can confirm that the problem is not from `clangd`.