Event Management Search Outside Territory Attendee Advanced Search is timing out when the user only searches for Postal Code. If other fields are used the search is completed. The Org contains a large number of account records (1+ million).
When searching for a single field (other than Postal Code), the where clause of the Search query contains only that field.
However, when searching by the Postal Code field, the where clause contains the Zip_vod__c and the Zip_4_vod__c fields using an OR relationship operator. This query uses many resources and it is more likely to timeout.
Veeva recommends using the Search Outside Territory feature with more selective searches in order to avoid any query timeout.
CRM Help Documentation: Adding Attendees to an Event