"Error in FNE protocol: null" while checking out license from LLS (server) using Java client kit

[#1]

Symptoms:

It was observed that when sending the capability request to the local license server using Java XT client kit, it throws below error.

ERROR com.magnet.licensing.core - Error during server request
com.flexnet.licensing.b.b: Internal error: Error in FNE protocol: null.
at com.flexnet.licensing.b.e.a(SourceFile:287)
at com.flexnet.licensing.b.i.bc(SourceFile:3767)
at com.flexnet.licensing.a.u.<init>(SourceFile:67)
at com.flexnet.licensing.a.t.getResponseDetails(SourceFile:2902)
at com.flexnet.licensing.a.t.addTrustedStorageLicenseSource(SourceFile:156)
at com.flexnet.licensing.a.t.processCapabilityResponse(SourceFile:178)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at clojure.lang.Reflector.invokeMatchingMethod(Reflector.java:167)
at clojure.lang.Reflector.invokeInstanceMethod(Reflector.java:102)
at com.magnet.licensing.core$send_capability_request.invokeStatic(core.clj:43)

Diagnosis:

Scenario used to replicate the issue was to upgrade the LLS from 2018.09 to 2021.02 and Java Client kit from 2015.09 to 2020.12. We observed here that customer was still using the old FlxCore.dll/FlxCore64.dll which was present in 2015.09 in to the upgraded Java client kit 2020.12. These old dlls were not compatible with the latest version of Java Client kit and hence while sending cap requests it was giving error.

Solution:

It was suggested to replace he FlxCore.dll/FlxCore64.dll with latest version in the Java XT client kit to solve the problem.