insufficient privilege: Not authorized while assigning schema to object privilege

Hi,

In my trial HCP i have created two user usr01 & usr02 and performing below activities:

i) login to trial HCP with SYSTEM user.

ii) assigning schema usr02 to user usr01

iii) while saving im getting below error

404 - Granting privilege 'SELECT' on SCHEMA 'usr02' failed: insufficient privilege: Not authorized

my requirement is to assign object privilege of usr02 schema to user usr01. could anybody please let me know what im missing here.

Thanks