Firebase cloud messaging server key showing disabled

Question

I'm trying to push a new android application to the play store. when I tried to add a new app to my one signal account it asked me for a firebase server key and a sender id. So I went firebase - settings - project settings - cloud messaging from here I got my sender id but the server key is disabled. This is the error it's showing Cloud Messaging API (Legacy) Disabled If you are newly integrating messaging into your app, use the latest Firebase Cloud Messaging API (V1). If you are an existing user of Cloud Messaging API (Legacy), consider migrating to the latest Firebase Cloud Messaging API (V1). What should I do to get a firebase server key?

Answer 1

It seems the server key of Cloud Messaging API (Legacy) is the only way at this moment.
I also came across on this issue recently and felt very confused on the term Server key as the new API didnt offer such key.

I came across the issue in Azure Notification Hubs.
Please check the following issue to see any follow up
https://github.com/MicrosoftDocs/azure-docs/issues/95498