Assuming it’s been like that for a while and without any other details, make sure:
-
The system it’s running on has access to the internet (see)
-
There are no firewall issues- typically, ERPNext uses 80, 443, and… 6787(?) when hosted as a domain with nginx up and running, or 8000 and 9000 when running locally. These are the defaults; your configuration may vary. Easiest way to see if the issue is something firewall-related is to just briefly disable any firewall you know of between you and the host system and see if it works. If so, reenable the firewalls and look into what ports are configured vs what is needed.
-
From your bench directory (default is ‘frappe-bench’) on the host system, run:
bench update
bench restart
sudo service nginx restart
If the site is set up, you still error with the firewalls down, and the update/restart regime doesn’t work, take a look at the error logs and see if anything pops out. If there is a repeating, quasi-repeating, or timestamp-corresponds-to-your-access attempts message, post a screenshot.