I created new distrubution groups in Exchange online.
I then created on prem security groups (universal).
I can see them in exchange online.
However i cant add them to the created distribution groups?
Can this be done with premium ? or is there an other way ?
There is no AAD Premium requirement for that, but in order for Exchange to "recognize" the group, it needs to be mail-enabled/have a valid email address. "Pure" security groups don't qualify.