Unable to connect to server while on Network, VPN allows connection ok

Expected behaviour

Client should connect to server when on that network

Actual behaviour

Client unable to connect to server - reports ‘invalid HTTP code received for status.php: 0’
But if I am outside network and connect via VPN client connects fine

This behaviour happens with three servers. Two are bare metal OCIS setups (5.0.9) and the other is listed below. All three allow connections while connected via VPN but not when inside the network. All three allow you to log into the server via the browser. If I try to connect a windows or linux client to the server it works fine.

Steps to reproduce

  1. Join Network
  2. Attempt to connect client to server.

Server configuration

Operating system:
Ubuntu 24.04

Web server:
Apache 2.4.58

Database:
mariadb 10.11.8

PHP version:
7.4
ownCloud version:
10.13.4

Storage backend (external storage):

Client configuration

Client version:
5.3.1.14018

Operating system:
macOS 15.1

OS language:
English