Received from Shal Farley at 4/3/2019 09:22 PM UTC:
As an anti-spam measure, your invitation list will be reviewed and (presumably) approved by Groups.io. It may take a few hours for that to happen, maybe days but not usually that long.
I'm thinking it would be a very good idea if the answer to this repetitive (an aptly descriptive word, not a criticism) question were contained within the message sent to an Owner/Moderator who invites "too many" people at once.
That approach should eliminate the regularly expressed confusion over this situation.
Jim H
