I was not able to find any documentation on error 75, you could try to contact Apple Support directly by call or chat.
The iTunes logo with charging cable indicates that you iPhone is in recovery mode. Apple Support made a video describing what to do next, I will link it below. When you get to iTunes you can try to update the iPhone, in that case you will not be erasing it. In case that does not resolve the issue, you will have to restore it, by clicking restore instead of update. This will reset the iPhone back to factory settings and all content will be erased of the iPhone. You can put your content back if you have a backup of your iPhone.
https://www.youtube.com/watch?v=csJAEyvvruY
https://www.youtube.com/watch?v=7s8-zLG9ySQ&t=135s