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The Horizon Console dashboard displays an alert for unrecognized requests for XML API protocol connection.There is no adverse impact on the user's session Logline similar to the sample below is seen in the Horizon Connection Server logs: [ConnectionServerHandler] Incrementing the warning count : Reason : unrecognized request detected Note: These alerts are typically classified as false positives with Horizon 2209, and 2212. With 2303 and later, these alerts should be investigated to ensure a consistent experience with the Horizon Client. However, when you are on an edition such as 2209 or 2212, If the user's sessions are impacted when this alert is seen (sessions disconnected etc), then this is a Load Balancer persistence setting issue. The load balancer is misrouting requests to the wrong connection server. For recommended Load Balancer persistence setting please see Monitoring health of Horizon Connection Server using Load Balancer, timeout, Load Balancer persistence settings in Horizon 7.x and 8 (56636)
This is caused when a user is trying to connect to the connection server with an expired session cookie.
'View Unrecognized Session Count ' is a new feature introduced in Horizon 2209, which causes these alerts(harmless) in the Horizon Dashboard. VMware Horizon 8 2209 Release Notes View Unrecognized Session Count was added to the Connection Servers and Gateway Servers tabs in the System Health dashboard (Monitor > Dashboard) in the Admin Console. This allows administrators to troubleshoot random disconnections of end-user sessions due to unrecognized requests received either at UAG or at the Connection Server.Horizon 2303 (8.9) and Later:VMware Horizon 8 2303 Release Notes Enhanced error handling has been added, This event being logged will be indicative of traffic not being routed to the expected connection server. [EventLogger] Error_Event:[BROKER_DETECTED_UNRECOGNIZED_SESSIONS] "ConnectionServer MyBroker detected 2 unrecognized requests for XMLApi protocol connection Loadbalancer Investigations: Load balancers can be removed temporarily to confirm the source of the errors.For recommended Load Balancer persistence setting please see Monitoring health of Horizon Connection Server using Load Balancer, timeout, Load Balancer persistence settings in Horizon 7.x and 8 (56636)Subject Matter Expert assistance through a support engagement with your load balancer vendor is encouraged and is often an efficient path to resolution. Host Redirection: For those scenarios where it is not realistic to disable a load balancer and wish to minimise disruptions during investigations, A connection server feature from Horizon 2209 & later can help avoid issues with affinity control. From UAG 2303, Unified Access Gateway Support for HTTP Host Redirect complements this feature for issues with devices and also contains its Host Redirection Feature Client IP Changes: If a Horizon Client's incoming IP changes during an existing authenticated session, this may be recorded as an unrecognised request. Reference: Unified Access Gateway Support for HTTP Host RedirectUAG Configure Horizon Settings - Honor Connection Server RedirectHorizon Installation and Upgrade - Enable Host Redirection