I had the same issue, but I’d made some changes to some files so I thought that was what caused the problem, guess not.
I deleted options.txt and restarted ospi.py, didn’t work.
I looked around at some other files but couldn’t see anything that might cause this problem.
Since I’ve only been experimenting with this program, I wasn’t using it to irrigate, I took the nuclear option and deleted the OSPi directory and reinstalled with:
git clone https://github.com/Dan-in-CA/OSPiRan ospi.py and everything worked perfectly.
Unfortunately the nuclear option means I don’t know what caused or fixed the problem. If someone would like to do a better investigation I suggest renaming your current OSPi directory and doing a fresh install using the git clone above. Verify the new ospi.py works fully. Then one by one copy your old data files into the new install (after renaming the new data file as a backup) and see if it breaks it. Then compare the old and new files and look for differences.