1. Log in as administrator at https://portal.microsoftonline.com/
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2. Go to the ‘Exchange’ Admin section:
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3. In ‘Exchange admin center’ go to the ‘permissions’>’admin roles’ and choose ‘Discovery Management’
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4. On the ‘Discovery Management’ screen, ‘ApplicationImpersonation’ role should be added (+ button), and administrator as a member (result shown below):
4a. adding ‘ApplicationImpersonation’ role:
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4b. adding ‘admin’ as a member:
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After these steps, user ‘admin’ will have impersonation rights.