Deleting issues - Assets

Deleting issues - Assets

We have 6 assets that we can't manually delete in the Assets module of ServiceDesk Plus.
 
This is the error message:
FAILURE :Exception while processing the request.

Please report the problem to the system administrator. Support file will have the error trace to analyze the problem and which can be created at Support -> Create Support File.

 
How can I delete my assets?

                  New to ADSelfService Plus?