The CA WA Agent aliases in the agentparm.txt can result in wrong or erroneous SNMP alerts. If the aliases have been added as an agent in the Manager (scheduler) side, then any changes on the agent side must match with all the aliases agent definition on the manager side.
Why do I keep getting AGENTDOWN messages?
CA Workload Automation Agent 11.3/11.4
The following errors may cause managers (schedulers) to think agent is down or not responsive.
TCP/IP Controller Plugin.Receiver pool thread <Regular:2>.CybReceiverChannel.receive[:158] - Conversation from 10.10.XX.XX:30001 to 10.10.XX.XX:7520 arrived
05/21/2018 12:37:XX.XXX 1 TCP/IP Controller Plugin.Receiver pool thread <Regular:2>.CybReceiverChannel.receive[:234] - cybermation.library.communications.CybConversationException:
Unexpected encryption type. DES received. AES expected.
The error indicates that the CA Agent received an incorrect encryption from the manager. If you have recently updated the agent and started receiving these errors, then check to make sure that Agent name, port, and encryption have been properly updated on the manager side.
Note: If you have aliases defined in the agentparm.txt, then any updates will need to reflect to the aliases entry (for the agents) on the manager side as well.
If your manager has agent entry called ALIAS11, then updated the settings for it, e.g. port, encryption.