Zabbix SSH-based check error

[sticky]

I'm trying to configure action to run script after trigger get some threshold.
In the events of the host I see that ssh comand fails with error:

"Public key authentication failed: Invalid key data, not base64 encoded"

But I able connect to this machines with private key used in configuration.
I've tryed to debug it and found these lines in the log file:

9615:20151202:191859.079 ssh_run() supported authentication methods:'publickey,password'
9615:20151202:191859.079 End of ssh_run():NOTSUPPORTED
9615:20151202:191859.079 End of zbx_execute_script_on_terminal():FAIL
9615:20151202:191859.079 End of zbx_execute_script():FAIL
9615:20151202:191859.079 In add_command_alert()
9615:20151202:191859.079 End of add_command_alert()
9615:20151202:191859.079 In DCget_nextid() table:'alerts' num:1
9615:20151202:191859.079 query [txnlev:1] [select max(alertid) from alerts where alertid between 0 and 9223372036854775807]
9615:20151202:191859.080 End of DCget_nextid() table:'alerts' [210676:210676]
9615:20151202:191859.080 query [txnlev:1] [insert into alerts (alertid,actionid,eventid,clock,message,status,err or,esc_step,alerttype) values (210676,38,1424822,1449076739,'hostname.com':/etc/zabbix/my_script.sh',2,'Public key authentication failed: Invalid key data, not base64 encoded',1,1);


The same key makes authorizations without any probles:

ssh -i key.pem [email protected]

Somebody know why it alerting about "base64"?