Fuel Line Keeps Popping Off of Fuel Rail
 

Hello, so me and my friend couldn't get our 1993 Volvo 850 to start. We thought it might have something to do with the fuel injectors so we took the fuel rail off. We found out that they were fine, put the fuel rail back on, put the injectors back in their sockets, and went to crank the engine. However when we started to crank the engine, the fuel line popped out of the fuel rail. There was some type of screw next to it and we figured this might be what holds it in, but when we tightened it, the fuel line still popped out. Is there something else that is supposed to hold it in? Would love for some feedback. Thanks.