Why is Two-Sided printing not working in Pages?

Hello Enver,

Thank you for using Apple Support Communities. Based on your post, you receive an error when attempting to print two-sided from the Pages app on your Mac. We'll do our best to assist.

If you've recently updated your Mac, we'd check for a Pages update: How to manually update apps on your Apple device You mentioned they were recently updated, but Big Sur very recently updated, so it's good to double check for that.

Are you able to select another page size and print two-sided? If not, are you able to share this document/file to another computer and print it on your printer successfully?

Have you checked for any updated printer drivers? See: Update printer software on Mac

Hoping to hear back, take care!

Hello Enver,

In that case, try to reset the Mac's printing system: Reset the Mac printing system to solve a problem

Then add your printer back: Add a printer on Mac

If that doesn't sort it out, then we'd recommend to bring this to Apple's attention and Contact Apple Support

Wishing you the best, cheers!