Should have mentioned this earlier. Sometimes flared fittings can be a bit troublesome.
When you disconnect and reconnect your fittings to check for the issues mentioned by Buckshot, it often helps to tighten and loosen and retighten the fittings a few times to get the flares to seat and seal a leak. Helps to also use "flare nut" wrenches on the fitting nuts as they will cause less distortion when tightening.
