Could not save Firebase (FCM) server key
We currently implementing and setup everything for the push notifications. Unfortunately I stuck at the step where we have to add the FCM server key to our server. When we insert the key and click save the following error occurs: "Couldn't update plugin: Cannot read property 'indexOf' of undefined". I follow step by step the documentation so this should be fine.
Just to be sure. Here a screenshot of the input field:
Does someone has the same problem or can give me an advice how to proceed here?