Have you upgraded your hardware? Have you upgraded ROS in your devices? Have you changed anything in the configuration? Have any other ISP installed new antennas in the area?
It is hard to belive that all three cards and coresponding anntenas have suddenly problems. Have you replaced your RB433 with other device?
No change anything configuration, only channels because interference.
Have you replaced your RB433 with other device?
Yes, in antennas have RB433AH only 3 cards R52N, and recently I create VLAN for authenticate PPPoE clients on RB3011. Only this.