Can't add items to collections?

[jackel7]

Whenever I try and add an item to one of my ebay collections as of late, it comes up with a message saying, 'Sorry, you can't add another item to your collection now. Go to your profile to delete items from this collection before adding more.' When this first happened, I thought it was because the collection was really full, because it had a lot of items in it, but when I tried to add the item to a different collection, the same message came up, despite the collections have drastically different item amounts. I have tried creating new collections, and that worked for a while, but now they too are coming up with the same message, and when I go to collections page to try and delete things it comes up with 'Hmm, something's not working. Please try again.'

Does anyone know what causes this, or how to fix it?