Can't export or save compund path to SVG

I'm trying to export a compound path to SVG and get the message "Could not export content to SVG". 

I have created 100+ icons on indivudial artboards. They are all simple shapes with few anchor points and most of them are compound shapes. The idea is to later on convert them to a font to be used in XML, therefore they (not all, but many) need to be compund paths to be read correctly and I need to use artboards to make sure the spacing is correct so they align in the end. When I had made the first 3-4 icons I did a test export and everything went fine. Now I get the message "Could not export content to SVG".

- All layers are unlocked (don't know if that could matter).

- I have tried Save, Save as Copy and Export. 

- I check "Use artboards".

- I have tried exporting only one artboard.

Please help! Thank you 🙂