Emails are not sent from mobile device

Hi, I’ve just noticed, that contact form doesn’t send emails from my mobile device (“Send” button doesn’t react, even though it’s active, and I can press it). No notification is shown, after I press the button. From my laptop everything works fine.

I tried to clear website’s cache, but it didn’t help. I use iPhone 6 (iOS 12.5.5 – last version for my device). And I checked from Google Chrome web browser (also last version for my device).

What could possibly went wrong? Thanks in advance for an answer!

The page I need help with: [log in to see the link]