You need to allocate the tokens from the QMC.
Once you do that (either by user or by a rule) the users can access the hub.
See the following for further help:
In addition to Eliran's link - the attached PDF is also very handy as a quick reference guide to granting access via the QMC.
Page 5 in particular worked very well for me.
Hope this Link helps :
I am also facing the same issue previously
and also find the PDF link .