PLA stuff the nozzle

I have a problem with my Vertex delta 3D printer, after 3 or 4 layers, every time it’s like the PLA is stuffing the nozzle and the PLA is not coming out of the nozzle anymore. In fact, we can see the PLA moving backwards every 3 or 4 seconds because the engine can no longer push it. I disassemble the nozzle and the top part is filled with PLA. I clean everything, fix everything, but each time it starts again. I try many settings but each time it the same issue.

Hello FranckBenh and others,
I have the same problem with de K8400. The extruder keeps clogging. I replaced the heating element and the sensor, replaced the PTFE tube of exactly 23mm. I have changed the throughput speed via this forum, see attachment.
It drives me crazy, disassembled the extruder dozens of times to solve the blockage, the screws are wearing out and a mountain of failed prints !!
Could it be the filament? Lately I have from
Please HELP.
Greetings AukeEEPROM instellingen

Repeated clogging can be from using a temperature too high for the filament brand or leaving the nozzle hot with no flow for a long time. There is no temperature calibration so the thermistor may not accurately sense the temperature, or the published printing temperature may be too high. For PLA I use 190 C as the nozzle temp, and have almost no clogs.