Disconnection Error in IS Server Log for Universal Messaging

We have UM with 3 realms servers, realm1 and realm2(another instance) are on same server, and realm2 is on another server.
In Integration Server log below error are seen:

[ISS.0153.0998E] [WMM.UM.ALIAS.03] Alias IS_UM_CONNECTION was disconnected: state = STARTED; clusterTryAgainAttempt = -1
[ISS.0153.0049E] UM connection alias IS_UM_CONNECTION was disconnected from its primary UM session. The primary UM session will automatically attempt to reconnect 5 time(S) before stopping the UM connection alias.

and below is the error in nirvanalog for that particular period of time.

Tue Apr 17 02:54:58 CET 2018],UserManager: User @ Logged Out using nhp, Reason : java.io.IOException IO : Input exceeded input buffer size, session established for 19 seconds, Session Id = a0ab2900000000 ID: 10.80.138.84:52806
[Tue Apr 17 02:54:58 CET 2018],UserManager: User @ Logged In using nhp ( DataStreamListener:false Admin:false OS:Linux Version:2.6.32-696.10.1.el6.x86_64, Java 1.8.0_65 Client Build : 9.8.0.0.13321 Build Date : January 30 2015 ) Session Id = a0af4e00000000 ID: 10.80.138.85:55848
[Tue Apr 17 02:54:58 CET 2018],Protocol: HTTPD: Invalid protocol handshake detected. Has cookie but no such session exists. Warning 10.80.138.85:55852 Supplied Cookie:
[Tue Apr 17 02:54:58 CET 2018],Protocol: HTTPD: Invalid protocol handshake detected. Has cookie but no such session exists. Warning 10.80.138.85:55856 Supplied Cookie:
[Tue Apr 17 02:54:58 CET 2018],Protocol: HTTPD: Invalid protocol handshake detected. Has cookie but no such session exists. Warning 10.80.138.85:55858 Supplied Cookie:
[Tue Apr 17 02:54:58 CET 2018],Protocol: HTTPD: Invalid protocol handshake detected. Has cookie but no such session exists. Warning 10.80.138.85:55862 Supplied Cookie:

Please suggest

Regards,
Prashant

Check if you the cluster configuration are correctly set for A-A-A. From UM do you see one master and two slave nodes?

Also, what is your UM version and make sure you have applied latest fixes both server and client (IS) side.