Stroller stuck on one side. How do I close it?
If it doesn't close (and it did before), try cleaning and oiling it and gently fold it. If that doesn't work, you will need repair (or a new stroller), because most probably some internal mechanism broke or got lopsided and now the side won't close. You cannot put it back wth sheer force, you might break it completely, so, customer service / repair place it will have to be.
Your -very berry- Eli.