The electronic resources environment contains many areas where various systems touch, creating ample opportunity for access errors. In this presentation I will briefly cover these systems, the ways in which they interact, and the kinds of errors that can be caused by mis-matches between systems. I will then use the scenarios sent by the Technical Services Roundtable to illustrate ways to diagnose different error types. Finally, I will cover a few tips for prioritizing multiple errors, reporting them to others, and tracking their resolution.