maximum learner

Hi,

I have a learning path that I made a group of learner for. When initially I enrolled the learners in the group, they received the invitation and could take the training. Later, I added some extra learners and they received the invitation. Now, it seems that when I add new learners in the group, they don't receive anything. Is it because that there is a maximum quantity of learner I can add in a group? They always stay ''pending'' in Reach 360 and when I ''resend'' they don't receive anything either.

Thank you for helping out with this,

M-P