I recently made some network changes and moved by Deco M5 units into access point mode.  Everything seems to be working fine with the new configuration but the Deco's are reporting they have no internet access, even though all the wireless clients access the internet just fine.  I suspect that the new router is blocking some specific traffic that the Decos are using to test their internet connectivity.  

Here's my network config:

<ISP Modem> --- <Mikrotik Router> ---- <Deco M5> ---- <switch> --- <Other Deco M5s>    

                                                    |

                                                    I --- <switch> ---- <wired clients>

Yes, I'm using ethernet backhaul

As I said, everything was working just fine when the M5s were running in router mode.  The clients that are wirelessly connecting to the M5s can browse the internet without any problem so the problem just seems to be that the M5 "think" they can't get to the internet when in actuality they can.

The Mikrotik router is serving up addresses via DHCP and is setting the DNS server to be itself.  I've tried having to server up 8.8.8.8, 8.8.4.4 as the DNS servers for the DHCP clients but that had no affect.  I've rebooted the M5s several times and also tried switching them back to router mode (and then back again) to no avail.  

Thoughts?