I get the following error message whenever I try to build to an actual device (works fine when using the simulator, and I can build to and install via TestFlight without issue):
Unable to install "AppName"
The certificate used to sign "AppName" has either expired or has been revoked. An updated certificate is required to sign and install the application.
Everything was working fine, then this error started appearing for seemingly no reason. I have tried the following fixes (multiple times, and in varying orders), but nothing has worked:
Managed to solve the issue by moving the apps source files to a new directory. Still no idea what exactly was causing the issue, but this fix works well enough.