Did you notice that illusions can be removed for free?
Did you maybe stack up an insane number of deeds?
Nothing (except getting rid of the stated above) can save you now.
Inventory Full - Illusions taking up inventory space
Inventory is full and Illusions fill it up completely?
I can’t find the dev response to this anymore (they archived parts of the forum making it invisible to us commoners) but just for your info: Hedge said that the cap was 1000 if I remember right.