https://community.cisco.com/t5/network-security/failover/m-p/3939613#M132433 <P>The most likely cause is physical layer between the two devices failed - either a bad cable or intermediate switch.</P> Sat, 12 Oct 2019 11:55:38 GMT Marvin Rhoads 2019-10-12T11:55:38Z https://community.cisco.com/t5/network-security/failover/m-p/3939604#M132431 <P>Both units failed due to comm failure, can I know the reason?</P> <P>&nbsp;</P> <P>Also, what that means "failover state check"; is it mean that the failover link has connection failure?</P> <PRE class="con-NoMargin hist-break-word">&nbsp;</PRE> <P>&nbsp;</P> <PRE class="con-NoMargin hist-break-word"><BR />Primary unit: ------------------ show failover history ------------------ ========================================================================== From State To State Reason ========================================================================== 11:46:25 CEDT Oct 10 2019 Sync File System Bulk Sync Recovered from communication failure 11:46:40 CEDT Oct 10 2019 Bulk Sync Standby Ready Recovered from communication failure 11:46:49 CEDT Oct 10 2019 &lt;--- More ---&gt; Standby Ready Just Active HELLO not heard from mate 11:46:49 CEDT Oct 10 2019 Just Active Active Drain HELLO not heard from mate 11:46:49 CEDT Oct 10 2019 Active Drain Active Applying Config HELLO not heard from mate 11:46:49 CEDT Oct 10 2019 Active Applying Config Active Config Applied HELLO not heard from mate 11:46:49 CEDT Oct 10 2019 Active Config Applied Active HELLO not heard from mate 11:49:13 CEDT Oct 10 2019 Active Failed Other unit reports that I am failed 11:49:15 CEDT Oct 10 2019 Failed Cold Standby Recovered from communication failure 11:49:22 CEDT Oct 10 2019 Cold Standby Just Active Failover state check &lt;--- More ---&gt; 11:49:22 CEDT Oct 10 2019 Just Active Active Drain Failover state check 11:49:22 CEDT Oct 10 2019 Active Drain Active Applying Config Failover state check 11:49:22 CEDT Oct 10 2019 Active Applying Config Active Config Applied Failover state check 11:49:22 CEDT Oct 10 2019 Active Config Applied Active Failover state check 11:50:04 CEDT Oct 10 2019 Active Failed Other unit reports that I am failed 11:50:09 CEDT Oct 10 2019 Failed Cold Standby Recovered from communication failure 11:50:10 CEDT Oct 10 2019 Cold Standby Sync Config Recovered from communication failure &lt;--- More ---&gt; 11:50:26 CEDT Oct 10 2019 Sync Config Sync File System Recovered from communication failure 11:50:26 CEDT Oct 10 2019 Sync File System Bulk Sync Recovered from communication failure 11:50:40 CEDT Oct 10 2019 Bulk Sync Standby Ready Recovered from communication failure ========================================================================== Secondary unit: ------------------ show failover history ------------------ ========================================================================== From State To State Reason ========================================================================== 11:47:09 CEDT Oct 10 2019 Failed Cold Standby Recovered from communication failure 11:47:10 CEDT Oct 10 2019 Cold Standby Sync Config Recovered from communication failure 11:47:26 CEDT Oct 10 2019 Sync Config Sync File System Recovered from communication failure 11:47:26 CEDT Oct 10 2019 Sync File System Bulk Sync Recovered from communication failure 11:47:39 CEDT Oct 10 2019 Bulk Sync Standby Ready Recovered from communication failure &lt;--- More ---&gt; 11:47:51 CEDT Oct 10 2019 Standby Ready Just Active HELLO not heard from mate 11:47:51 CEDT Oct 10 2019 Just Active Active Drain HELLO not heard from mate 11:47:51 CEDT Oct 10 2019 Active Drain Active Applying Config HELLO not heard from mate 11:47:51 CEDT Oct 10 2019 Active Applying Config Active Config Applied HELLO not heard from mate 11:47:51 CEDT Oct 10 2019 Active Config Applied Active HELLO not heard from mate 11:49:12 CEDT Oct 10 2019 Active Failed Other unit reports that I am failed 11:49:15 CEDT Oct 10 2019 Failed Cold Standby Recovered from communication failure 11:49:24 CEDT Oct 10 2019 Cold Standby Sync Config Recovered from communication failure &lt;--- More ---&gt; 11:49:57 CEDT Oct 10 2019 Sync Config Sync File System Recovered from communication failure 11:49:57 CEDT Oct 10 2019 Sync File System Bulk Sync Recovered from communication failure 11:50:04 CEDT Oct 10 2019 Bulk Sync Just Active HELLO not heard from mate 11:50:04 CEDT Oct 10 2019 Just Active Active Drain HELLO not heard from mate 11:50:04 CEDT Oct 10 2019 Active Drain Active Applying Config HELLO not heard from mate 11:50:04 CEDT Oct 10 2019 Active Applying Config Active Config Applied HELLO not heard from mate 11:50:04 CEDT Oct 10 2019 Active Config Applied Active HELLO not heard from mate ========================================================================== ASA-ENCIS-01/pri/stby# show failover state State Last Failure Reason Date/Time This host - Primary Standby Ready Comm Failure 11:50:04 CEDT Oct 10 2019 Other host - Secondary Active Comm Failure 11:48:18 CEDT Oct 10 2019 ====Configuration State=== Sync Done Sync Done - STANDBY ====Communication State=== Mac set</PRE> Sat, 12 Oct 2019 11:26:57 GMT https://community.cisco.com/t5/network-security/failover/m-p/3939604#M132431 Tuba 2019-10-12T11:26:57Z https://community.cisco.com/t5/network-security/failover/m-p/3939613#M132433 <P>The most likely cause is physical layer between the two devices failed - either a bad cable or intermediate switch.</P> Sat, 12 Oct 2019 11:55:38 GMT https://community.cisco.com/t5/network-security/failover/m-p/3939613#M132433 Marvin Rhoads 2019-10-12T11:55:38Z