Problem with MPLS

RouterOS Forwarding Protocols
1

I had a OSPF routed network that works ok, I wanted to add MPLS for VPLS

I followed the wiki examples over and over, but when it comes up, in LDP neighbour, I see the neighbour and local/transport address only for 5 seconds, and it flips from dissapeared, to there, to gone again every 5 seconds, no addresses appear in the address field and MPLS fails to start

On the other router, nothing ever shows up in LDP neighbour

Can MPLS be blocked by firewall? What do I have to allow?

2

646/udp
521/udp LDP transport session

646/tcp
521/udp LDP hello protocol

make sure those ports are not blocked.