The issue is explained here:
Licensing errors might occur if you upgrade the Java environment or upgrade applications to version 6.0.5 or later

First occurrence
6.0.5

Problem
If you upgrade your version of Java to a fix pack that was built after April 2017, or you upgrade an application to version 6.0.5 and later and are using WebSphere Liberty, licensing errors might occur. The errors occur because earlier licenses were signed with the MD5 algorithm, which is now blocked by newer versions of Java.

For example, the License Key Management page for Jazz Team Server might display the following error in the Description field: CRJAZ1236I A development time license is being used. Similarly, the jts.log file might display the following error: CRJAZ0965I The file was not a valid server or client access license activation key.

The latest license files no longer contain the MD5 algorithm because IBM and Oracle Java introduced restrictions on JAR files that are signed with weak algorithms and keys.

Workaround
The licenses in the IBM Rational License Key Center were updated to use a different signature algorithm.

After you upgrade your server to version 6.0.5 or later, obtain the updated licenses from the IBM Rational License Key Center to replace your current licenses. If you previously used floating, token, or authorized user single install licenses, install their updated versions. Your existing user license assignments are kept during the installation of the updated licenses.

Your version of EWM is out of support. Please open a case with support anyway. In the past few years, a lot of encryption related stuff has been revoked. It is well possible that something like that happened with your Java version and that cases the issue you see. Without any log data, this is however just speculation.