I’ve run into random connectivity issues like that too, especially when using certain ISPs. A while back, I couldn’t get into Gmail and YouTube while everything else worked fine. Turned out DNS routing was messed up from the ISP end. Restarting everything didn't help either, so I just changed to Google's public DNS and that sorted it temporarily.
Nowadays, I use a mix of services and don’t rely on one provider for key stuff like email. I even have backup email accounts that I got from
here in case of downtime or access issues. Been handy more than once.