Have just encountered error 6A80 after clearing a minor paper jam help! My machine is an MP550

I went online and found the HP8600 user manual and this is their solution to the error code 363 that you reported, which I copied off their site. Hope this works for you:

• Turn Error Correction Mode (ECM) off, if you encounter the same error repeatedly. Click this link HP All-in-One and Fax Products for more information on enabling or disabling ECM.
  

  
  

  NOTE: Error codes that apply specifically to ECM have ECM listed next to them.
  

  
  

Error Code: 356, 357, 358, 359, 360, 361, 362 ECM, 363 ECM, 364 ECM, 365 ECM, 366 ECM

Definitions

• The remote user pressed the Stop key, causing the session to be terminated.
• The remote machine encountered a system problem such as no paper or a paper jam. This prevented the fax from receiving any more pages, and caused it to terminate the session prematurely.
• The call-waiting service can cause this error. The click, heard for an incoming call, is actually a momentary disconnect of the line.
• The remote machine encountered an incompatible feature causing it to terminate the session.

Solutions

• Configure the remote machine for document reception by clearing any paper jams, loading sufficient paper, and clearing any other error messages.
• Configure the local fax machine to use a slower reception speed.
• Enable or disable the ECM setting.

Solution video Error 6A80

www.youtube.com/watch?v=F3S5Dcp6s8Yv

Per your user manual, here is a list of all the LED status':

Jam ()

Orange

On

A paper jam has occurred. (See Clearing paper jams.)

Online/Error ()

Off

• The machine is off-line.
  

Green

On

• The machine is in power saver mode.
  

• The machine is on-line and can receive data from the computer.
  

Blinking

• When the LED slowly bilnks, the machine is receiving data from the computer.
  

• When the LED rapidly blinks, the machine is printing data.
  

Red

On

• The cover is opened. Close the cover.
  

• There is no paper in the tray. Load paper in the tray.
  

• The machine has stopped due to a major error.
  

• Your system has some problems. If this problem occurs, contact your service representative.
  

• A toner cartridge has almost reached its estimated cartridge life[a]. It is recommended to replace the toner cartridge. (SeeReplacing the toner cartridge.)
  

Blinking

• A minor error has occurred and the machine is waiting for the error to be cleared. When the problem is cleared, the machine resumes.
  

• Small amount of toner is left in the cartridge. The estimated cartridge life[a] of toner is close. Prepare a new cartridge for replacement. You may temporarily increase the printing quality by redistributing the toner. (See Redistributing toner.)
  

Those errors that deal with paper jams. An error code "6A80" can either represent a sheet feeder error or a debugging unit. This means that there may be scattered bits of paper or other debris trapped inside the unit itself. The potential for this error is high; when the paper is removed from a jammed feeder, bits are prone to fall off and cause this error code. The user must inspect the inside of the printer thoroughly. This error can result from problems with the unit serving or the electronic card; however, the most likely cause is debris caught inside the printer interfering with the printer's operation.

The 6A80 indicates that the mechanism called the `purge unit' does not work correctly. In some cases after a paper jam, some paper gets in the unit. Try this:
Turn on the unit and open the cover. Hopefully, the printhead will come to the center. If it doesn't, unplug the printer and try to move the printhead by hand, to the left. Do not force it. If you are able, get a flashlight and inspect the area inside the unit to the right. There may be bits of paper in that area. Being careful, remove it with a tweezers or some such tool.
If you cannot see anything, then the machine will need to be dismantled for service. I recommend authorized service.

[6A80] & Light Blinking 12 times = APP Position Error. An error occurred in the APP motor. Maybe foreign material or paper debris around the PURGE UNIT (at the printer most right hand side) or Auto Sheet Feed area.

6A60 error is an APP (Application Printer) position error. It means that an error has occurred when the motor was running during the purging operation on start up.Check the sheet feeder and purge unit.Sometimes pieces of paper stuck in purge unit.

Thank you!

6A80 is APP position error.First, make sure there is no paper jam anywhere in the machine.. look inside, rear, where the paper tray (output)
is, etc to see if you find any shreds or torn paper that may have gotten stuck and you didn't see.Look carefully in the zone of Purge unit, using flashlight in the right side on printer.Check the sheet feeder.If this not help your printer need service.

That error says there is something jammed in either the purge assembly or the sheet feeder on the back not able to turn. The purge assembly is on the right where the printhead parks for cleaning.