It means something that has gotten in the way, such as a traffic tie-up on the highway.

“Tie-up” is a phrasal verb. These are words put together that combined will have a meaning that may not be directly related to the words themselves. “Tie-up” can mean a link between companies but also to bind something with rope or string. To tie means to fasten or attach and up means up as opposed to down. In the context you are talking it takes a meaning of figurative binding of companies or organizations. Hope it helps !