Tiny printing in email body

I’ve been using eM Client free version for about a year. Today all the content in the body of incoming emails is shoved to the right side and so tiny it can’t be read.I haven’t changed any settings and can’t find a place to change this to go back to normal,

click on a message in the reading pane, hold down the [ctrl] key and scroll the mouse wheel up or down.  If your mouse doesn’t have a wheel use [ctrl] and the “+” and “-” keys.  You can use either the numeric pad keys or the keyboard keys.