1. Go to Cloud Formation service in the region where Veeam Backup for AWS server is deployed.
2. Select appropriate Stack from the list by clicking its name in the Stack Name column.
3. Go to the Resources tab.
4. Find the <SERVER_NAME>-VeeamImpersonationRoleV1-XXXXXXXXXXXX in the Logical ID column.
5. Go to the role description by clicking it's name in the Physical ID column.
6. Copy Role ARN by clicking Copy to clipboard in order to add it to the trusted list for recently added role:
7. Go to the Roles
tab in Identity and Access Management (IAM) service
8. Find the custom role you want to add into Veeam Backup for AWS.
9. Select it by clicking its name in the Role Name
10. Go to the Trust relationship
11. Click Edit trust relationship
12. Add the following JSON.
"AWS": "ARN of the role from step 6"