@AshikAliLive Which ONT were you using previously? Also, which Syrotech ONT do you have? If you could show full screenshots of the ONT management UI (both old and new) and pics of the physical device, it would be helpful. (Asking cause there are different models with different model ids, but underneath many of them behave the same)
The issue is that the new ONT is not whitelisting on the OLT, so depending on your existing ONT and new ONT, we might be able to clone the auth parameters and see if it work.
@ps1193 This is due to the ONT whitelisting at the OLT level. The mac binding at the PPPoE auth stage (if applicable) is different and as you said can be cloned, but that doesn't appear to be the case here.
Some Syrotech ONT models do support changing the auth parameters, if not the only option is to the contact whoever manages the OLT (LCO or BSNL) and get them to allow the new ONT to register with the OLT.
You don't have optical signal in the screenshot shared for syrotech ont.
Also check that the port bound is the same you are using for wan connection. For bridging i selected all so if i need to check some signal or conifg etc i can just connect to other lan or use ont's wifi.