2509864 - Cannot decrypt message error in AS2 sender channel

You have set an AS2 sender channel and your partner sends encrypted messages. During the decryption of the AS2 message you get the following error:

Catching Cannot decrypt message: java.lang.IllegalArgumentException: the message is not encrypted for Version: 3
Serial number: <SERIALNUMBER>
Signature algorithm: sha1WithRSAEncryption (1.2.840.113549.1.1.5) 
Issuer: CN=<issuer of the key>,C=<country>
Valid not before: Thu Jun 10 10:00:00 CEST 2010
      not after: Mon Jun 10 10:00:00 CEST 2030
Subject: CN=<subject of the key>,C=<country>
RSA public key (2048 bits):
public exponent: 10001
modulus: <modulus of the key>

Certificate Fingerprint (MD5)  : <MD5 of the key>
Certificate Fingerprint (SHA-1): <fingerprint of the key>
Extensions: 1

at com.sap.aii.adapter.as2.ra.api.util.BouncyCastleUtils.decryptAndDecompressAS2Message(BouncyCastleUtils.java:659)
at com.sap.aii.adapter.as2.ra.api.AS2Receiver.parseMessage(AS2Receiver.java:425)
at com.sap.aii.adapter.as2.ra.integration.ChannelDispatcher.receive(ChannelDispatcher.java:404)
at com.sap.aii.adapter.as2.servlet.AS2DispatcherServlet.doPost(AS2DispatcherServlet.java:254)

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• SAP enhancement package 1 for SAP NetWeaver Process Integration 7.1 >= SP08
• SAP NetWeaver 7.3 >= SP05
• SAP enhancement package 1 for SAP NetWeaver 7.3
• SAP NetWeaver 7.4
• SAP NetWeaver 7.5
• SAP Process Integration, business-to-business add-on

SAP NetWeaver 7.3 ; SAP NetWeaver 7.4 ; SAP NetWeaver 7.5 ; SAP NetWeaver Process Integration, business-to-business add-on 1.0 ; SAP enhancement package 1 for SAP NetWeaver 7.3 ; SAP enhancement package 1 for SAP NetWeaver Process Integration 7.1

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