I am using Indesign 2020 v15.0.02 and i am unable to export a large width document to PDF as I keep getting the Background Tasks Error. I have never seen this before.

I need to export a large mm doc design for our new outdoor sign and can't send to the printers as it wont export properly.

I've looked online but cant fix it myself despite trying tips.

Please help this is driving me insane!