This is speculation, but ...

The "on error" fires and you jump to the "notfound" label. At this point,
you are in "error handler" mode. You then loop  and potentially have another
error. But you're already in error  mode, so a further error will not cause
the jump.

You could try putting an "on error goto 0" in the "notfound" code. That
might fix things.

Otherwise, you might need to exit from the loop and/or the sub to clear
error mode.

Speculation only - I could easily be completely off track.