Failed to create provisioning profile

In my case this error disappeared when I changed the "Bundle Identifier" to something less generic (e.g. adding some random numbers at the end)

Change the bundle identifier to something more unique.

If you are following a tutorial and just put a generic identifier then adding a few numbers to the end will likely solve your issues.

i.e. if you had HelloWorld change it to HelloWorld12345

Check the schemes menu at the top of the Xcode project window. Look at the destination you're trying to run in. If you run in the simulator, you don't need to sign your project.

If you run in a device, you need to attach the actual device. It must not say "generic device".