Why does hp laserjet CP3525 says A4 in tray 2?

SOURCE: My HP LaserJet 4200 prints fine from tray 2, but will NOT print envelopes from tray 1. It WILL print on regular paper from tray 1, but will not print envelopes. What gives? I've already rebooted the

Are there settings on the control panel of your printer?
Is the tray 1 the MP tray? (The one that flips towards you)
If so, can you change the settings of the Tray 1 to Envelope on the control panel?

I hope this helps.

SOURCE: HP LaserJet 2430dtn - "Tray 2 open or empty"

This model have an issue with the level indicator, take out the tray casette and shake it a little. You see it from the front, the level get stucked sometimes, indicating that there is no paper loaded, even if the casette is full.

SOURCE: 13.01.00 paper jam tray 2

The pickup rollers are worn out. Replace them and your problem will be gone. While you are sourcing them, use some alcohol. This may give them a little more life.

SOURCE: hp laserjet p3005dn tray1 manual feed problem

you can choose mp first in "paper handing" printer menu or print tray1 is A4 default in properties of printer software.

SOURCE: default paper tray selection for HP LaserJet 4200tn

1) When the printer receives a print job, it selects the tray by trying to match the requested paper type and size with what has been loaded in the trays. Using an “autoselect” process, it searches all available trays for the paper that satisfies the request, starting with the bottom tray and ending with the top tray (tray 1). The printer begins printing the job as soon as it finds the proper type/size.

2) If paper is loaded in tray 1 and tray 1 is set "TRAY 1 TYPE=ANY" and "TRAY 1 SIZE=ANY" on the
Paper Handling menu, the printer will always pull paper from tray 1 first.