Cannot change field security permissions as administrator

Hi,

I am trying to change the field security roles for ADX as the system administrator but CRM is not allowing me to do so, says "Caller b2628794-f7f5-e711-a8a3-00224801a6b7 doesn't have Create privilege for attribute 'adx_identity_logonenabled' of entity 'contact'". I have checked that my user is definitely an administrator. Also the fields I am trying to change don't appear in all field security roles, which is strange. Has anyone had a similar issue before?

Thanks.