Runtime Error Custom Module Adapter 7.31

Hi experts.

We've developed a custom module adapter to be used in HTTP_AAE sender adapter. The deployement is successfull, the module is started but we are facing this error at runtime:

Error in processing caused by: com.sap.aii.adapter.http.api.HttpAdapterException: ERROR_IN_MODULECHAIN, null

¿Any idea what can be happening?

We are working with version 7.31 SP 10 Java only stack installation.

Thanks a lot.

Kind regards.

Christian.