Adding members to multiple boards under several teams with free edition Edited

[rmoroney]

Hello, hoping someone can help here. I am running a workshop next Monday to Thursday and its split up in to technical advisors (Teams) of which there are 5 and then boards under those. There are 26 boards in total spread across the 5 teams.

There are approx. 20 managers i need to add to each specific board, as i cannot enable all members in the team to access all boards - they are client accounts.

For the leaders of my business i am adding as admins, but everyone else i am adding as a guest so they can still use the board in the workshops but not have the admin privilege. 

There are a a total of approx. 150 users across the 26 boards that will be provided access, some with all, some with a few and some with 1.

I successfully added to 2 boards in 1 team, and then 1 board in another team, however when i went back to the team with the 2 boards already added - to add another, the people came up red and i was unable to add anyone. I then tried with other boards and had similar issues. 

I do know that various members are not yet registered in Trello, and therefore will need to do so via the link that comes to them when i add via the boards so is this limitation perhaps trello stating i have too many guests pending registration or what?

Is it just that Trello needs time to digest all the additions, because i am adding everyone at a fairly fast pace.

I have read so many articles which states there are no limitations to users so i dont know whats going on. Can someone please help as my workshops are on monday!!!

[rmoroney · Accepted solution]

Great news i solved my own question - Seems Trello cannot handle more than 3-4 group additions at once and just rejects any other additions for a good 10-15mins. If this happens to you and it starts rejecting additions to boards, wait 10-15mins and then go for it again. Pretty annoying but i am assuming it may not be efficient enough to handle bulk amounts of invitations at once which is weird.