We use the Ruby SDK and randomly receive
Unable to retrieve the FCM server key for the recipient's app errors, even tough we’re pretty sure the key is correctly set up.
By random, we mean even tough we send thousands of notifications each day, we had errors on December 25 and 26 of 2018, none in the following days, returning now again in Jan 1st and Second, but regarding only a very small % of our notifications sent.
Do we need to provide a different key for each release channel? That’s the only thing we can come up with for the randomness of the error.