Not sure if I've worded this correctly, so help me if I didn't.
I'm a web developer hosting a Wordpress website for a client (I'm not really a Wordpress expert, just trying to maintain the site while building a new one). The site is hosted on Cloudways, the DNS is managed through telenet.be (a Belgian internet company).
The site works fine, except for one organization that works with its own administrative NAT network. For some reason, they are not able to reach the site from that network.
I have checked for security plugins in the Wordpress site, blocked IPs and ports at Cloudways (hosting) and telenet (dns) level, but everything seems fine, there's also no sign of the client's IP in any access logs. When trying another site that's hosted on the same Cloudways server with the same IP however, it works fine.
I'm obviously missing something here, if someone can help me find a solution (or a way to find the actual problem) that would be much appreciated.