IndexError: bpy_prop_collection

[Digital X]

I just got hit with this error, that I haven't seen before.

Every object has a material applied. I'm only going by the last line because the rest to me, doesn't make sense. What's going on here?

Edit: After making a new blend file, and exporting only the main building, that alone WILL export. So i'm exporting as per each object is added, no idea what happened before or how I fixed it tbh.

[ external image ]
i math symbol

[Dotec]

why do you still use 3.6?

[Digital X]

I've just been on it for a while, what's best to use?

[Madkine]

3.6 is still the last officially supported version, but higher versions can be used with unofficial updated versions of SCS tools.