Usually, during an update of Cognos BI version, server name change, so we need to change URI for Excel CAFE.
First URI used for connection is hardcoding in Excel CAFE document.
Resolving the problem
1. Open MS Excel
2. Click on the 'IBM Cognos' button in the IBM Cognos toolbar
3. Cancel the log on screen
4. In the CAfE options add the new System-Gateway-URI
5. Place your cursor on the first Excel cell (upper-left) of the current sheet.
6. Double click on this cell
>> A window opens ... "Select Pack"
7. Select the name of the new connection created at the step 4
8. Once validated, CAFE menu appears.
9. Remove your old URI in CAFE options
10. Save your document