Welcome to the forums.
Please consider taking a few minutes to provide even vaguely rudimentary information about your system. You have posted the NAS equivalent of "My car won't start, what should I do?"
Some helpful hints for composing a more useful problem report are listed in the Forum Rules, conveniently linked at the top of every page in red.
Among the useful things to know would be, detailed hardware manifest of your system, including especially (but definitely not limited to) the type of ethernet card in use, what your upstream network looks like, what version of TrueNAS we're talking about, and any other information such as whether there are link lights or indications of link in the GUI.
Without some more detail, you are likely to get very low quality answers that are the equivalent of throwing darts at a dartboard blindfolded.