Facebook messenger has alert "no internet connection" when using CP 3800 Security Gateway

[Deadvp]

Hi everybody,
I am using a CP3800 device running Gaia OS R81.10 to replace a CP4600 device running Gaia R77.30. However, when using the CP3800 device, I encountered the error that Facebook messenger sometimes has no internet connection and cannot send or receive messages. When using the CP4600 device, Facebook messenger works normally.
I currently only use the Firewall feature on the CP3800 device and do not use any other features. In addition, I also tried updating the hotfix patch and tried updating to Gaia OS R81.20 but it did not solve the problem.
If anyone has encountered a similar situation or has any ideas, please help me!

[_Val_]

is your HTTPS Inspection on?

[Deadvp]

Thanks for your reply,

I have not enabled HTTPS Inspection. I want to make sure it meets our firewall requirements before using any other feature. So I have not enabled other features including HTTPs Inspection

[_Val_]

Is there anything in the logs?

[Deadvp]

I don't detect any log drops. I'm checking so that our LAN can connect to all destinations without going through any blocking rules.

[_Val_]

Also, just to make sure. No Application Control and no URL Filtering, right?

[Deadvp]

Yes bro. I haven't used them yet. Only Firewall Policy based

[Deadvp]

I don't detect any log drops. I'm checking so that our LAN can connect to all destinations without going through any blocking rules. 

I also don't use URL Filter or Application Control

[_Val_]

OK, how about NAT rules? Do you have any for LAN? How do they look?

[Deadvp]

We do not create NAT rules on the CP3800 device. We perform NAT on the Router device. CP3800 only serves as the default gateway for LAN

[CP_Chris]

Do you detect the outgoing connection in the logs? Based on the information given, I would start an fw monitor looking for the relevant traffic and verify I am getting traffic on the internal and external interfaces in both directions. That may give you an indication of where to start looking for issues.