Mikrotik rb1100ahx2 dropping connection

Hello, I have a problem with the mikrotik rb1100ahx2… It is connected by wire to 17 asus rt-12n+ wireless access points.. all acting as wireless bridges (the main cable from mikrotik router in connected to on of the AP lan ports and not the wan port)

Asus access points settings
-firewall disabled
-dhcp disabled
-nat disabled

The whole network is working fine… But the mikrotik randomly drops wan connection of the whole network from a period of time (sometimes for 20 secs and sometimes up to 2 minutes )from ISP configured on Ethernet 13 as ppope over a wireless p2p on the roof…

I tried troubleshooting the problem knocking my head to the wall without a solution.

I even tried to remove all the APs and only connect to 1 AP and the same.

BUT when when I removed all the APs and connected only my laptop by wire to the mikrotik router, it was stable as hell with not a bit of was or ping drop.

The drop only happening at wan but ping to the whole network including the mikrotik router never drops.

HELP !!!