The strangest thing happened today--I wasn't able to create a vertical spread or any other recognized spread type. The following procedure has been done by me for a year without any problem: I right-click on a blank line in TWS and click "generic combo." I enter the underlying "ES" and the exchange "GLOBEX." Then I select the "single tab." I select "vertical spread", then sell combo. I enter my legs. I typically trade bull put options, so one leg shows selling 1 put near the money and the other leg shows buying 1 put further out. Both legs have the same expiration date. When I click to set it up, I get a message: "This combo can only be executed as Non-Guaranteed." Well, I proceeded to create the combo. The legs appear correctly, but the spread line is different. It shows "Smart" as the exchange (not GLOBEX), and there are no quotes appearing for the spread. If I try to enter my own quote, I get another message--basically I can't execute the spread. As a matter of fact, I tried several recognized spread types, and they all were treated as above. I send a message to customer service inquiring. Has anyone else encountered this problem?