Troubleshooting Tip: Unable to connect to remote FortiGate after firmware upgrade on the local FortiGate

In rare situations, access to a remote FortiGate GUI after upgrading the local FortiGate to 7.4.5 might be lost. To resolve the issue, create a bypass firewall policy to confirm if the issue is related to the security profiles. 

1. Login to FortiGate's GUI and navigate to Policy & Objects -> Firewall Policy, and select Create New.  

2. Specify the new policy name, and set the incoming interface and outgoing interface, as well as the source IP address of the test device in the form of <w.x.y.z>/32, as shown in the image below. Destination and Service should be set to 'all', and NAT should be enabled.

3. Test connecting to the remote FortiGate again via the GUI. If the issue persists, clear the FortiGate related cache using the following commands:

di test app urlfilter 2

di test app dnsproxy 1

Note:

Double check the admin-sport in config system global if the issue persists, as the wrong admin-sport may have been provided even if the IP address is correct. Alternatively, double-check the port value via the GUI under System -> Settings.