Yes, I have seen the many other tickets with this subject name, but they did not solve my problem. All of the directory paths in my "User Include Directories" in Project preprocessor options are correct. If I navigate down the full paths specified in the errors, which the error says "cannot be found", I find the file I am looking for. So the path is definitely correct, and the files definitely exist.

When I click on the files from the project panel on the left, I get this error that says the file can't be read or opened. What is happening?
I just cloned the repo from git, if that makes a difference. I am using SDK 14.2.0, NRF52840, S140.
Note, I did not download a separate zip for the softdevice, as the softdevice appears to be included in the SDK. This is the same setup as I have on my other computer, where the compilation works:
