with --fleet-type ON_DEMAND everything is ok.
My second problem, which i mention before backfilling request does not work in c# or net.core 2.0 env, you can find additional info in StartMatchBackfill and C# Server SDK for Unity issue
SessionId: arn:aws:gamelift:us-east-1::gamesession/fleet-a1f9df30-6cc7-4984-814f-63a01a4ecd36/f8bbc071-26e2-4fe7-abe9-f36907cbb919, matchMaking: arn:aws:gamelift:us-east-1:231684332637:matchmakingconfiguration/DestinyStarsMatchmaking2, Backfill request failed with error: [GameLiftError: ErrorType=SERVICE_CALL_FAILED, ErrorName=Service call failed., ErrorMessage=An AWS service call has failed. See the root cause error for more information.]
My third problem is impossible to delete matchmaking configuration (tickets still exits? can you delete it manually? DestinyStarsMatchmaking
2018-02-15 13:18:24 UTC+0400)