My ONU is in bridge mode.
I'm from suburban area, so BSNL has given me the connection.The issue persist with the PON device Mac address not being whitelisted in the OLT.
I had the opposite issue where MAC binding did not let me use transparent vlan bridge mode in my TP-LINK ARCHER C6.So, I had to use VLAN tagging.The LCO is really dumb.
Ask your LCO,he has the solution.Ask your LCO to reset Mac binding or restart the OLT.
It usually makes OLT to re-authenticate the ONT.Just a guess as I have seen this happen.