Well this one is baffling me. Org says you can have up to four lines and 400 characters including bb code or 200 excluding.
My sig is one line, no images and contains four urls (or would if it'd work!) - and definitely doesn't have more than four hundred character, yet every time I try to save it it tells me I'm using more than the four lines allowed. I've checked and double-checked that there are no hidden hard returns and there is definitely just one line.
I'll get a screengrab if needed