GRE Tunnel between Balance One and Cisco router

Hi Team,

I am currently replacing old remote cisco router but i am unable to make the GRE Tunnel work between the Balance One Core and the Cisco hub router.

Below the configuration of the GRE Tunnel from the remote old cisco router 891F

interface Tunnel101
description CONNECTED TO HUB
bandwidth 100
ip address 20.1.1.4 255.255.255.0
no ip redirects
ip mtu 1400
ip nhrp authentication eamf1234
ip nhrp map multicast dynamic
ip nhrp map multicast 41.203.79.158
ip nhrp map 20.1.1.1 41.203.79.158
ip nhrp network-id 1
ip nhrp nhs 20.1.1.1
ip tcp adjust-mss 1360
tunnel source 41.204.20.22
tunnel mode gre multipoint
tunnel key 8710

Below the tunnel configuration on the HUB Cisco router

interface Tunnel101
ip address 20.1.1.1 255.255.255.0
no ip redirects
ip mtu 1400
ip nhrp authentication eamf1234
ip nhrp map multicast dynamic
ip nhrp network-id 1
ip tcp adjust-mss 1360
no ip split-horizon
tunnel source 41.203.79.158
tunnel mode gre
tunnel key 8710

Any hint/suggestion thanks ?