2647623 - Failed to Base64 decode the given value

You have configured your AS JAVA System to be the Service Provider in a SAML Communication but this SSO is failing, in the Troubleshooting wizard trace file we can see the below error:

Could not extract SAML2 message from request.
[EXCEPTION]
java.lang.SecurityException: com.sap.security.saml2.lib.common.SAML2Exception: Failed to Base64 decode the given value: xxxxx
.....

Caused by: java.lang.ArrayIndexOutOfBoundsException: while trying to store to index xxxxx of a byte (or boolean) array with length xxxxx , loaded from local variable 'decoded'
at com.sap.engine.lib.xml.util.BASE64Decoder.decode(BASE64Decoder.java:403)
at com.sap.security.saml2.lib.common.SAML2Utils.decodeBase64(SAML2Utils.java:298)
.....

Service Provider could not extract SAML2 message from request. Reason: com.sap.security.saml2.lib.common.SAML2Exception: Failed to Base64 decode the given value:

LOGIN.FAILED
User: xxxxxx
IP Address: xxxxxx
.....

Login Module                                                               Flag        Initialize  Login      Commit     Abort      Details
1. com.sap.security.core.server.jaas.EvaluateTicketLoginModule             SUFFICIENT  ok          exception             true      
2. com.sap.security.saml2.sp.SAML2LoginModule                              OPTIONAL    ok          exception             true       Service Provider could not extract SAML2 message from request.
3. com.sap.security.core.server.jaas.CreateTicketLoginModule               SUFFICIENT  ok          false                 true      
4. com.sap.engine.services.security.server.jaas.BasicPasswordLoginModule   REQUISITE   ok          false                 false     
5. com.sap.security.core.server.jaas.CreateTicketLoginModule               REQUISITE   ok          false                 true      
No logon policy was applied

• Release Independent
• SAP NetWeaver

SAML Response, Failed to Base64 decode the given value, Base64, Decode, Decoding, Service Provider could not extract SAML2 message from request, Service Provider, extract SAML2, SAML2 , KBA , BC-JAS-SEC-SML , JAVA SAML 1.1 and 2.0 , BC-JAS-SEC-LGN , Logon, SSO , Problem