Hi @Saqer   There is a performance filter in the knowledge base search you can filter by to see a few articles.

Database fragmentation can be a cause for performance issues.  It is recommended to set up and run daily and weekly maintenance against the RetinaCS database to ensure stability and performance. For more information, refer to  KB0017248. 

Ensure the customer is running a supported version of Beyondinsight Password Safe as there were a few old issues fixed such as in article: KB0019557.

I would also check the log files or system event viewer for any timeout errors and search the knowledge base. Sometimes it is how the environment is set up and the configuration needs to be changed. For example, narrowing down the amount of accounts returned by a query. 

Encourage the customer to open a case with BeyondTrust Support to investigate.