iMovie exporting really slowly/not at all

I am trying to export a 9min video from iMovie. I have changed the resolution and quality to the lowest possible settings and the file won't export. The circle in the top right of the iMovie screen that shows how much of the project has dowloaded will load to a certain point and then stay there. I have a 2month old MacBook Air, there is only a small number of files in my iMovie library and I have no other programs open when trying to export the project.

I have looked at forums and YouTube online and followed most of the recommendations I have found but still no luck.

Thank you in advance