In ServiceNow you search for an item, but the searches return "No records found." You are given a hyperlink to a case, but you see "Record not found" despite being logged into the web UI for ServiceNow. What is going on or what is wrong?
It is possible that the hyperlink had a typo or that the search term literally could not find a matching record. But there is another explanation that is possible.
It could by that you do not have membership to the appropriate group (behind-the-scenes thus you have no visibility to it). The behavior you find in ServiceNow could be attributable to your account not having insufficient permissions. ServiceNow has a SQL database on the back-end. Ask your ServiceNow administrator to see if your account is a member of the Access Control List. You may want to post a question on community.servicenow.com or look here.