HP 7520 Envy Printer Paper mismatch error

[Marla_1967]

I'm having a similar problem to many others who have posted about "Paper mismatch". I have tried *every* possible solution other than updating my drivers, because for some reason, the update process doesn't work-maybe my OS is too old? I am using Mojave 10.14.6. I don't have more than 23GB left on my hard drive-could this be why the updating of the drivers/firmware isn't happening? 

I did try and carry out an Alignment test (Align Printer) and it did print the page out, and it looked fine. So what is strange is that I can carry out the printer function tests and the printer does print, but for some reason, printing a Word document or an email from Outlook for Mac (as examples) results in "paper mismatch". Everything was working fine as of a few days ago. 

I know for certain that my paper size is correct. I've tried unplugging the laptop from the wall socket; tried removing and adding the printer name in the queue; tried turning it on and off....tried every obvious solution. 

I also know for certain that nothing has changed on my laptop as far as software goes-I don't actually have enough hard drive space to upgrade my OS to the latest, so there have been no changes like that, that would account for the paper mismatch error message. 

Do you have any other thoughts on how I might solve this problem? 

Update: I am unable to update my drivers and firmware, presumably because I am still on OS Mojave 10.14.6 but what I *have*  noticed is that I can *copy* using the touch screen on my printer-that printer function works fine. It seems to only be a "paper mismatch" problem when  I try and print from Word or Outlook for Mac (the two main Applications I use for day to day work). Can anybody advise on a resolution to this problem? 

[Marla_1967]

I solved the problem myself:). In the Printers and Scanners set up area in Settings for Mac-I chose the name of my printer instead of Airprint and this seems to have solved the problem. I had read in an article that we should set the printer up as Airprint & I just thought I'd test what would happen if I changed that to the printer model "HP 7520" and it now prints fine, no paper mismatch error:).