ERR_DISABLE: loopback error detected
ERR_DISABLE: loopback error detected
Aug 26 12:47:28.248: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/23, changed state to down
Aug 26 12:47:29.251: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/23, changed state to down
%ETHCNTR-3-LOOP_BACK_DETECTED: Loop-back detected on GigabitEthernet1/0/23.
After entering no keepalive , shutdown , no shutdown interface configs issue fixed.