Plesk Migration: critical error: Object of type filter is not JSON serializable

In the 'List of subscriptions' I selected the subscriptions I wanted to migrate, then the content that must be transferred:

• Migrate mail messages
• Migrate website files
• Migrate database data (tables, rows, etc)
• Migrate external IDs

and Subscription owner
- Copy to source customer/reseller
In the end no subscription was loaded for migration and the error message appeared

Failed to fetch configuration data from Plesk servers
Cause: Object of type filter...

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