MikroTik

I am having an issue accessing My cliant equipment when I use PPPoE. I am using a RB450G, with OS Level 4. I am trying to access them via the IP address shown for the user under the active connections tab. I have also manualy added a local IP address to a user, and it still will not work. I can ping the IP from within the Mikrotik, but I can not ping those IP's from outside the mikrotik. Is it a routing issue? It worked for a while, but has recently quit working.
Any Ideas?

I had the same issue after upgrading my RouterOS version. Any ideas?

looks like routing problem. Device from which you are trying to access CPEs must know how to reach them and vice versa.
Check whether CPEs have default route installed and then check if along the path to remote device are correct routes installed.