1.  check which subscriptions are not synced

• Login to Plesk > reseller > subscriptions 
• On the right side of the search button, you will be able to see down arrow key, click on down arrow key.
• In Subscription State select UNSYNCED

2. Click on the domain name of that subscription.

3. On the Right side under the account section, click on SYNC option

4. Once you click on sync it will be sync with the respective service plan, it may give you an error “Synchronization Failed”

5. If you get error then you have to check the customize settings, there is a possibility that reseller have customize the settings.

6. If yes then you have to calculate the values assigned by the reseller. 

• 1st check how many subscriptions are created.
• You have to check which service plans are assigned to them.
• E.g if the there are 20 subscription and in service plan the reseller with pluto plan have assigned 10GB storage per subscription, then it won’t sync.
• In pluto plan resellers have only 50GB storage, if you calculate 20 subscription with 10GB storage then it will be around 200GB.
• You need to check which subscription actually having the requirement of 10GB, if the service plan is using only 100 MB or 150 MB then you have create new service plan with 500Mb or 1GB and move that subscription into that service plan.
• Same you need to check for traffic, Database, mail quota etc.