After clicking the "All" button or similar UI Action on the Affected CIs Related List, the left side of the List Collector (slushbucket) has no results and instead says "List's data could not be retrieved"
An xmlhttp request which taks about 15 seconds and then returns with the message "Information could not be dowloaded from the server because the transaction was canceled".
A Slow query to pull back the data from cmdb or cmdb_ci for the list collector is reaching the quota time for that processor which is 15 seconds OOB.
Debug SQL and Business Rules to determine if there is a before Query Business Rule which is causing the issue, or if the default filter can be edited to make the query faster.
You can also change the quota rule to allow more time for the request if that query is absolutely necessary. (see below)
How to edit Quota Rules.