If you don't have quota left and use Mailmeteor free version, you can upgrade on our paid plans to unlock your sending limits. In all cases, you can check the "Merge status" column that indicate which emails have been sent and which have not.
If your G Suite account is new and under trial period, you may be limited to 400 emails per day instead of 1500 emails per day. Usually, the trial period lasts two weeks. We cannot unlock your sending limit as Mailmeteor relies on Google sending infrastructure.