Connecting Time capsule with a modem Air 5010

I changed my old modem for a Airties Air 5010.

Internet connection works well when connecting through Ethernet (on a PC because new Mac Pro have no ethernet port).

When I connect the modem to my Time Capsule all lights are green on the modem and the TC.

Airport utility shows TC green light but no internet connection (yellow) even though TC box tells wifi and internet connection are on green.

When I changed the modem for a SAGEM Livebox Pro V2 everything is working well.

I tried (almost) everything like (dis)connecting, restarting but nothing worked.