ANDROID Forticlient VPN issue when using Hotspot connection

[EA94100]

Hello all,

We have a major issue with the Forticlient VPN connection.

.

After many tests, here is what we know :

1. When using the Forticlient app on an ANDROID tablet/phone with a direct wi-fi connection, it works flawlessly

1. When using the Forticlient app on an ANDROID device by using a phone's mobile data to connect the device to the internet, it doesnt work. We get the error message « show error:revoked by android reboot » 

1. When using the Forticlient app on an IOS device, it works perfectly either with direct wifi or a through a mobile hotspot.

We are always using the latest iOS, Android or Forticlient version available.

We have this issue since April 2025.

Our IT service is clueless. 

Does anyone here could help to sort this out? 

Thank you very much and have a great day!

FortiClient 

[Sheikh]

Hello @EA94100 

Which version of FortiClient is it? Have you attempted using any other versions of the FortiClient?

I mean, check with other versions to see if this helps you.

regards,

Sheikh

[EA94100]

Hello ! Thanks for replying :)

Ive tried with several android Forticlient 7.4.x versions. All not working with the hotspot connection. 

Not sure i can downgrade to a 7.x version. Or at least i dont know where to look and how to do it.  

[Sheikh]

Hello,

 - Check the certificate on the FortiGate side and ensure that it is valid. 

 - Try updating OS updates on mobile device.

regards,

Sheikh

[EA94100]

Im gonna ask my IT service but i imagine they already checked the validity.

Plus it should be valid right? The Forticlient VPN connexion works perfectly if using a Router wifi connection. The only case it doesnt work is when the android tablet where the Forticlient app is installed is using an hotspot connection from a phone mobile. 

All OS are up to date, on both side (tablet or the mobile phone used to share the connection). 

Basically : 

Android tablet/phone+ wifi (router) -> OK

Android tablet/phone + Wifi (from hotspot ) -> NOK

Windows + Wifi (router) -> OK

Windows + Wifi (hotspot) -> OK but we had to desactivate IPV6 on the PC side.

iPad + Wifi (router) -> OK

iPad + Wifi (hotspot) -> OK