503 API Error: "upstream dependency failed: DeviceCapabilitiesClient"

[niltti]

I'm trying to use the web SDK (as instructed in https://developer.spotify.com/documentation/web-playback-sdk/quick-start/) but am constantly running into the same error when initially connecting the player:

"code": 14,
"message": "upstream dependency failed: DeviceCapabilitiesClient; unhandled error: io.grpc.StatusRuntimeException: INVALID_ARGUMENT: upstream dependency failed: DeviceCapabilitiesClient client; (400) Bad Request",
"details": []

Although the request response indicates that the error has a status code 400, the request response itself has a 503 status code. Because of the error, none of the player events trigger either (ready / not_ready / initialization_error / authentication_error / account_error).

Thanks for the help!