Why this alert is displayed:
You have exceeded your cloud storage quota.
When the alert is deactivated:
Once the quota is increased or some archives are removed from the cloud storage.
How to troublehsoot:
1. Check the storage quota specified for the Backup account. Consider increasing the quota (see this article for help) or leave the field blank to allow unlimited storage for the user.
See also this known issue: Acronis Backup 12.5/12 and Acronis Backup Cloud: "The storage quota is exceeded"
2. Ask the user to remove incomplete (if there are any) backups. See this article for detailed instructions.
3. Ask the user to delete old backups (which they don't need anymore) from the cloud storage using the web restore interface:
A: In the Backup management console click Recover.
B: In Location, select Cloud and click Recover files.
C: In the web restore interface, select the machine which backups you want to delete.
D: Click on the gear icon and select Remove: