I now tried setting it to "unlimited" for every group but some users are still not receiving alerts...If only some users are getting tagged by your group alerts, be sure to check the "Maximum mention alerts per message" permission in the users>user group permissions>[your group] menu. We had a similar issue of only some users being tagged by alerts, and increasing that fixed it for us. To be sure it's set up correctly, you can also use the "Analyse Permissions" functionality of XF.
