hi everyone, pleaseeee i need some help and thanks in advance for your help. ive been having an issue with my ender 5 pro printer since a lot of time and I cannot find the cause. it start printing right but at a random moment, the extruder start rejecting new filament and the hotend stop printing material. I notice that if at that moment I replace the filament, then it starts working well again. also notice that when I replace the filament I had to push out with strengh to get the filament out, and when I take it out it looks like the picture. seems like at some point in the printing the filament get partially melted in the teflon tube and make the extruder to not be able to feed with more filament. It get solved changinf the filament, but that makes me be aware of the printing all the time, if I leave then the printing dont finish. I read somewhere that it may be the teflon tube coupler that is not ok and create a space between the tube and the nozzle and filament solidificates there and couses the issue, but I replaced the couple and it is firm. what else can be the issue??