The error related to 'Failed to get PD class info ' may be observed on the EX3400 device. These error messages have no functional impact and if the PoE transaction fails, it will automatically be retried.
'Failed to get PD class info
Usually when the log level is set to level info/notice these error messages may be seen in the logs.
The errors seen on the device:
Aug 1 01:08:56 JTAC-SWITCH fpc0 PoE: poe_get_dev_class: Failed to get PD class info Aug 1 01:13:30 JTAC-SWITCH fpc1 PoE: poe_get_periodic_status: Failed to get system info Aug 1 01:35:45 JTAC-SWITCH fpc1 PoE: Failed to read voltage measurements Aug 1 02:01:31 JTAC-SWITCH dc-pfe: PoE: Failed to read voltage measurements Aug 1 02:01:31 JTAC-SWITCH fpc0 PoE: Failed to read voltage measurements Aug 1 04:56:50 JTAC-SWITCH fpc1 PoE: poe_get_dev_class: Failed to get PD class info Aug 1 07:00:15 JTAC-SWITCH fpc1 PoE: poe_get_hip_power: Failed to get power info Aug 1 07:13:51 JTAC-SWITCH dc-pfe: PoE: poe_get_periodic_status: Failed to get system info Aug 1 07:13:51 JTAC-SWITCH fpc0 PoE: poe_get_periodic_status: Failed to get system info
These are informational logs and do not have any functional impact.
To suppress repeating non-impacting messages, refer to KB9382 - How to prevent certain syslog messages from being written to the log file. [juniper.net]