I´m probably having the same problem. I asked my host provider and told me to come and speak with wordpress support because there was nothing they could do.
In my case, I have installed the same wordpress three times and always happends the same. It´s working well, then the backoffice, the frontoffice or both go down. If I wait for a while It normally return but sometimes don´t and I have to delete and reinstall.
I have asked my host again about dns… they told me this:
The nameservers of your domain are pointing to us. The WordPress application is now coming up fine without any issues. If you are experiencing the issue, you can provide us the screenshot of the page to further investigate on your issue.
They have forwarded your issue to theie engineers for further investigation.
