Steps to reproduce:

1. Zabbix agent configured with TLS-PSK encryption. "TLSConnect=psk" and "TLSAccept=psk" in zabbix_agent2.conf
2. Host with zabbix_agent2 registered into server with TLS-PSK option for Connection to host and Connection from host. Same TLS-PSK identity and secret for both configuration (to host / from host)
3. Two zabbix proxies registered into server as passive proxies. Both with TLS-PSK configuration (Connection to proxy) correctly configured.
4. Agents with "Server=proxy1,proxy2" and "ServerActive=proxy1,proxy2" configured in zabbix_agent2.conf
5. Agent assigned to proxy1 in server
6. Templates with active and passive checks assigned to agent

Result:

1. Everything working fine and as expected. Server displays metrics and collects/receive data for agent checks (passive and active)
2. "Standby" proxy (proxy2) logging messages continuously (every 3 seconds per each agent) like below:

Sep 15 13:32:09 proxy2.zabbix.lan zabbix_proxy[604517]: cannot find requested PSK identity "agent1.corp.lan_C11e"
Sep 15 13:32:09 proxy2.zabbix.lan zabbix_proxy[604517]: failed to accept an incoming connection: from 10.13.25.2: TLS handshake set result code to 1: file ../ssl/t1_lib.c line 2750: error:14201076:SSL routines:tls_choose_sigalg:no suitable signature algorithm: TLS write fatal alert "handshake failure" 

Expected:

1. Everything working fine and as expected.
2. No noise messages are logged into "Standby" proxy (proxy2).