This issue occurs when Sphere is processing too much information with a limited time frame.  It often occurs, but is not limited to, running queries, reports, or importing a csv file through a form. 

To resolve the above examples, you can try to simplify the query or report, or import records through Contacts > Database Management > Manage Contacts > Import Data.

If the issue still occurs or your example is not listed above, please make a note of the code number, either by writing it down, or taking a screen shot. Chat with Support and reference this article. 
Please include the following information:
  1. The reference code.
  2. The time you received the error, and the time zone.
  3. What you were doing when you received the error.