1) Check the paper size in the printer settings to make sure you are using the appropriate size.
2) Check if the paper guides are too tight and correcting them accordingly.
3) Check the tray lock/release switch and make sure it is securely placed.
4) Make sure there are no cartridges blocking the paper tray.
5) Check to see if any debris has stopped the tray from closing.
6) If all of the previous steps do not solve the issue, restart the printer.