This can happen often due to changes in third-party libraries. You encountered this error after upgrading to Mendix version 9.24.12, it is possible that there is an incompatibility between the versions of Apache POI and the mendix runtime.
Below are a few steps to troubleshoot the issue:
1. Ensure there are no conflicting versions of Apache POI or other libraries in your project. Remove any duplicate or contradictory JAR files.
2 . Ensure that you are using compatible versions of all third-party libraries. Specifically, check the version of Apache POI being used and update it to a version compatible with Mendix 9.24.12.
Hope it helps!