Guessing it's the standard issue; using the broken current version of JoiPlay, 1.01.430.
You can either downgrade to 1.01.400 (https://apk.support/download-app/cyou.joiplay.joiplay/1622358000_vs-1.01.400)
(Make sure to enter JoiPlay playstore settings and disable auto-update, that would reinstall 1.01.430)
Or go into JoiPlay playstore settings and enable beta versions, which I hear beta 1.01.500 works.