led STOP and EXTF on CPU 412-2 PN

[Mohperso]

Hello, here I have a problem on an automaton equipped with a CPU 412-2 PN (6ES7412-2EK07-0AB0)

The PLC went into stop and all the LEDs on the front blink, on the technical doc I can't find any info on this state. Subsequently we made a general deletion of the PLC (which I find very long ...).
What does this state mean?

Then I reloaded the PLC to start on a good basis but it still does not go into run mode.

The STOP LED on steady and the EXTF LED on steady also, I checked the RJ45 connection part between the CPU and CU320 and a display but I did not see anything in particular.
Have you ever encountered this type of problem?

Thank you

[CoMod]

See Diagnostic buffer https://support.industry.siemens.com/cs ... t/14960968

The diagnostic buffer provides the user with the following options:

• Rapid detection of error causes and therefore increased plant availability.
  In the case of plant stoppage, evaluation of the events just prior to the STOP to find the cause of the STOP.

The diagnostic buffer is a ring buffer with separate diagnostics entries. In the diagnostic buffer, the diagnostic events are displayed in the order of their occurrence.
The first entry contains the latest event.
When the buffer is full, the oldest entry is overwritten with each new diagnostic buffer entry.
Depending on the CPU, the size of the diagnostic buffer is either fixed or can be set with parameters in the hardware configuration.

HWConfig
Select PLC
menu PLC>Module Information (or Ctrl+D)
for view online