Can't publish add-on Duplicate add-on ID found error

I am trying to Submit a New Add-on on uploading the add-on package
its says always “Duplicate add-on ID found” even though there is no addon with that id. even after changing the add-on id in manifest.json to something unique it always shows and error "Duplicate add-on ID found for every id.

Thank you.

Hey @webpocpluginextension, sorry to hear you’re having problems. What is the ID of the extension you are trying to submit? We can look into it on the back-end.

Separately – have you submitted an extension with this ID at any time in the past (as a self-hosted add-on, or as a new submission that was later deleted)? AMO does a case insensitive check for unique IDs at the time of a first submission; when new versions are uploaded, it does a case sensitive check on the ID to ensure it’s the same.

We are distributor of Firefox extension for dragon professional.

It’s ID is

Now we have done some modification to the same extension, while publishing it shows error as “Duplicate add-on ID found.”

Earlier we have used same ID for the Firefox extension in the year 2018.

Currently we have opened new account with same ID “” and faced the mentioned issue.

We are expected to publish our extension with the same extension id as we don’t want our existing customers get affected.