Cisco IOS & Route Map Problem

Folks,

I've been struggling with this for days, and I've completely changed topology multiple times, and this: https://imgur.com/a/OiLAfWA is what I've decided on.

I will focus on the Cisco 891F in the top left of the diagram for now. It has an internet connection with a /30 and a /28 IP address assigned to VLAN1 (with the /28 as a secondary). It also has an "internal" interface of 172.31.255.1/30 assigned to Fa0.

The Meraki MX84 is connected in routed mode with a real world IP on port "Internet 1" (second usable /28 IP). It also has another interface directly connected to the Cisco with an IP address 172.31.255.2/30.

I have the below configuration on the Cisco side:

---

!

interface Loopback0

ip address 10.30.10.1 255.255.255.0

ip policy route-map ROUTEMAP

!

interface FastEthernet0

ip address 172.31.255.1 255.255.255.252

duplex auto

speed auto

!

route-map ROUTEMAP permit 10

match ip address 10

set ip next-hop 172.31.255.2

!

access-list 10 permit 10.30.10.0 0.0.0.255

access-list 10 permit 10.40.10.0 0.0.0.255

!

---

I can ping 172.31.255.2 from the Cisco, but I cannot do a "ping 8.8.8.8 source lo0" -- this fails. A packet capture on the Meraki shows nothing, so I know it's a Cisco issue... but not sure where to go from here. I mean... this should be very basic...

Thank-you!