Problems with export as PDF in Illustrator - Please help!

Hi!

I'm experiencing quite some challenges with Illustrator at the moment. I've made some simple graphics for some banner printing for an event. The background has been made in PS - pretty simple with some blurred colors, and then there's 3-5 sponsored company logos on top. For some reason, the printing company wants the files in 1:1 scale (PDF). 

One of the banners measures 800x100 cm, which creates an extremely large file, obviously. This one I had no problem exporting as PDF at all though. The other one measures 540x100 cm - smaller dimensions than the first one - but refuses to export as PDF. I've tried pretty much everything in both Illustrator and Photoshop with different export settings but it's not working. It doesn't make sense though, when I had no problem exporting the big one. 

The error reads "Following files can't be exported:" and the name of the file. When I try to save it through Files > Scripts > Save document as PDF, it says "The dimensions of this page are too big", following "the operation was cancelled".

Has anyone tried something similar and found a solution? Any help is much appreciated, thank you!