3538865 - Unable to add back DR node using command sap_update_replication after DR drill test - SAP SRS

• The issue arises when attempting to add back the 3rd DR node in existing HADR after a DR drill test activity.
• While adding the DR node back using sap_update_replication add, site3 command, below error shows up:
  [TRACE] [Update Replication:286][RMA] - [com.sybase.ua.plugins.dr.] - Executing 'sp_hadr_admin config_bs, NULL, 'DR_node_hostname'' on the ASE at HA_node_hostname:4905.
  [TRACE] [Update Replication:286][RMA] - [com.sybase.ua.plugins.dr.] - SQL ERROR -- Message: 'Can't open a connection to site 'SYB_BACKUP'. See the error log file in the ASE boot directory.' SQLState: 'ZZZZZ'  Remote Code: '7205' Cause: ''.SQL ERROR -- Message: 'Can't open a connection to site 'SYB_BACKUP'. See the error log file in the ASE boot directory.' SQLState: 'ZZZZZ'  Remote Code: '7205' Cause: ''.SQL ERROR -- Message: 'Could not establish communication with Backup Server 'SYB_BACKUP'.  Please make sure that there is an entry in Sysservers for this server, and that the correct server is running.' SQLState: 'ZZZZZ'  Remote Code: '3220' Cause: ''.
  [TRACE] [Update Replication:286][RMA] - [ConnectionManager        ] - Terminate connection <2110161194(com.sybase.jdbc4.jdbc.SybConnection@742ccab)>: jdbc_sybase_Tds_HA_node_hostname_4905_master_HA_node_hostname_4905_DR_admin_213c9541cd6b4534d2dc759576ee323f (s/r/a/w/t/o) (164/0/0/0/0/0)
  [ERROR] [Update Replication:286][RMA] - [ConfigureLocalRSInstance ] - Task Configure a local Replication Server - Failed with error message - Failed attempting to record an entry for dump and load support between host 'HA_node_hostname' and host 'DR_node_hostname' or its alias.
  [ERROR] [Update Replication:286][RMA] - [ConfigureLocalRSInstance ] - Task Configure a local Replication Server - Failed with Exception - Message: 'Can't open a connection to site 'SYB_BACKUP'. See the error log file in the ASE boot directory.' Cause: ''.
  [TRACE] [Update Replication:286][RMA] - [ConfigureLocalRSInstance ] - Task Configure a local Replication Server - Failed with Stack Trace - Can't open a connection to site 'SYB_BACKUP'. See the error log file in the ASE boot directory.

• SAP Adaptive Server Enterprise (ASE) 16.0 for Business Suite
• SAP Replication Server (SRS) 16.0 for Business Suite
• SAP Adaptive Server Enterprise (ASE) 16.0 with High Availability Disaster Recovery (HADR) for Business Suite

sap_update_replication, site3, 3rd node, add, remove, teardown, sp_hadr_admin config_bs, SYB_BACKUP , KBA , BC-SYB-REP , Sybase Replication Server (standalone) , Problem