403 Error on Mobile only

My app’s URL: https://x39now.com

Help! I just published last night and all was working fine this morning. But this afternoon, I can’t get anything on mobile, just a 403 error that looks like this:

But someone else just logged in and told me how great it looks, and I can see the app on my laptop just fine.
I have rebooted my phone and nothing. Android Galaxy 8. Is this a chrome error?

Any help would be greatly appreciated, I have searched the forum and can’t find this issue.