FortiClient VPN only suddenly broke for 300+ clients

[pekoms]

So this issue really broke my brain.

First our license expired on our Fortigate 300E because someone forgot to renew them. This caused most of the traffic to stop going out until we disabled inspection etc

Now funnily enough after this all happened the FortiClient VPN just stopped working for like 300+ clients. The only client that seemed to work was for the Mac, Mobile and web-portals.

We were running 6.2.10 on the Fortigate and 7.0.3 on the clients.

We have now taken the leap to 6.4.9 on the Fortigate and 7.0.5 on the clients, still no go.

What is even more strange is that everyone can connect but there is no traffic received only sent out. This works if downgrade client to 6.4.8 or even use web-portal.

I am kinda hoping for some kind of fix to this other than downgrade 300+ clients to 6.4.8

Anyone come across anything like this?

[Anonymous]

Hello pekoms, 

Thank you for using the Community Forum. I will seek to get you an answer or help. We will reply to this thread with an update as soon as possible. 

Thanks, 

  Fortinet Community Team 

[jie]

Hello pekoms, 

If you check the below document you can see the highest version of supporting FortiOS 6.2 is FortiClient 6.4. FortiClient v7 is not compatible with FortiOS 6.2.

https://docs.fortinet.com/document/forticlient/7.0.0/ems-compatibility-chart

Please check the combability and see whether the issue still remains. 

Thanks,