If your iPhone 6s or newer displays error code: JMERBHT297 you should switch off WiFi for 2-3 minutes. After turning WiFi back on the error should be cleared. If the error message reappears delete known WiFi networks and add them again.
If your Android 10 or newer phone displays error code: JMERBHT298 you should switch off WiFi for 1-2 minutes. After turning WiFi back on the error should be cleared. If the error message reappears restart the phone.
If your Android 9 or older phone displays error code: JMERBHT299 you should delete all known WiFi networks and add them again. After reconnecting to WiFi the error should be cleared.