The solution is to install the iXp 11.4 Patch #4 which updates Jars up to 24 January 2025.
The ixp 11.4 Patch #4 is available under the following location :
IXP11.4.0-GA-Patch#4 - Cumulative Fixes FIX #99111393 | for MULTI-PLATFORM
Below the details of the fix included in Patch#4 :
2. Signed Jars expiration dates extended
The current set of signed jars will expire on Oct 17, 2022. After that point your browser may refuse to load the iXp GUI and AdminTool. With this release the signed jars will now expire on Jan 24, 2025.
Problem Number: 16151