I am also having the same issue as this user. I have however ordered fibre optic loop tool to try and isolate which module is failing. However i do not know where the modules are. Is anyone able to confirm details of where i can locate all the relevant modules.
Also this post and others similar have had no answer is there a another area in the forum which discusses MMI issues hence why no reply?
OP did you manage to get to the bottom of your issue?
Thanks