Dear @fegauthier ，

fegauthier wrote

I just update my controller from 4.2 to 5.3.1.

I have around 2700 WLAN Groups for 300 sites and now when I want to add new WLAN Group I have this error.

I can't add WLAN Groups anymore... Is there a way to bypass this?

Thank you so much for taking the time to report the issue to our community!

To better assist you, I've created a support ticket via your registered email address, and escalated it to our support engineer to look into the issue. 

The ticket ID is TKID220631172, please check your email box and ensure the support email is well received. Thanks!