You said that the site is working on your phone, but not the computer, correct?
If you have already tried restarting your network device, restarting your computer and your web browser, and clearing your cache, your next step would be to try flushing your cache and DNS settings.
This isn’t really an issue the article covers. It’s not just that you’re unable to open phpMyAdmin, it seems that any sort of contact with phpMyAdmin just doesn’t work from your end.
Fixing DNS cache won’t help here since phpMyAdmin is accessed on the naked IP. There is no DNS caching when there is no DNS.
My money is on some network level block or perhaps a virus scanner or security firewall of some kind restricting your access.