I'm using a mobile device and the Google Form submit button is greyed out. Is there a specific mobile issue?

Mobile devices are prone to specific issues, particularly if the form isn't fully responsive. Ensure your mobile browser is up to date. Sometimes, the page rendering on mobile devices may cause issues, try to refresh the form. If possible try switching to the desktop version of the form within your mobile browser settings to see if this resolves the issue. Finally, be sure that your device has enough available memory to load and submit the form properly.