I would suggest you to use below instead of JCO_AHOST and JCO_SYSNR:Use JCO_R3NAME with system ID of the target hostUse JCO_MSHOST with message server host name or IP addressUse JCO_MSSERV with message server port numberUse JCO_GROUP with the name of the logon groupYou can refer to below link to check a working example:https://sourceforge.net/p/rcer/git/ci/master/tree/net.sf.rcer.conn