Seems like there is another layer of protection on top of your WordPress install, either by your web-hosting company or whatever service that sits in front of your website before traffic is routed to it.
Its probably configured to not allow access to everyone and limit access by either IP address or some other criteria.
Suggest you check out any such protection that was configured under your hosting panel or reach out to your web-hosting company.
It can also be a WordPress plugin you configured, in which you would have to deactivate the plugin. You can do so by renaming the plugin folder (once identified) under wp-content/plugins, in a file manager in your hosting panel.
Ok thank you, I will try these options!