Sever error with RBR50

Hi,

So we've been experiencing a quite frustrating problem with our ORBI RBR50 system at home. We aren't able to find the solution ourself, so I thought I'd ask you guys. 

Everytime I try to connect my iPad Air (2020) to the ORBI-network a server login error occurs (as depicted in the image). Strangely enough, the WiFi works perfectly fine on every other device at home, with the exception of the iPad and my fathers iPhone 12. Because it's only affecting these two relatively new devices, we were thinking it has something to do with the chips of these devices, however, it's pure guessing. 

Does anyone have any experience with this problem and on how to solve it?

I hope to hear from you soon!

With kind regards,

Milan Gielen.