I've noticed that blacksmiths across Britannia have been unable to buy weapons and armor because their storage is full. I've consistently had trouble selling loot for about 2 weeks (cutting into my profits! ). Just wondering if lots of people are selling loot these days (and thus, full vendors) or whether this is a legitimate issue with NPC vendors.
I find if you click on the vendor and select the "buy" option, then cancel the action, it seems to free up some space on the vendors inventory to allow items to be sold again.
Well always works for me anyway - so give it a try