Export the subscription data using PS on the working server.
https://docs.citrix.com/en-us/storefront/current-release/configure-manage-stores/manage-subscription-data.html
Then remove contents of folder C:WindowsServiceProfilesNetworkServiceAppDataRoamingCitrixSubscriptionsStore on both Storefront Servers,
The follow the steps in the section “Restoring Data on a StoreFront Server Group”
Stop the Subscriptions Store service on working Storefront server..
Restore the data on non-working server using the Restore-STFStoreSubscriptions cmdlet.
Restart the Subscriptions Store service on servers StoreFront2.
It will then receive a copy of the data from StoreFront1.