Error: The specified item could not be found in the keychain

My project runs fine in the debugger, and until today there was no problem building. All of a sudden at the end of a build, at the linking step I’m getting this error:

“error: The specified item could not be found in the keychain”

That’s all, no item is identified in the dialog. This error dialog is put up by Xojo, not the OS, so I don’t think this is referring to the system Keychain. The built app runs, but I don’t know what might fail.

I’ve cleared caches to no avail.

Running Xojo 2019R1.1.

Anyone have any idea what this means, and better yet, how to identify what’s missing?