Hi @lindyrae,
I tested this in ACA 2017 with the default Project Navigator project, by selecting the four Structural Plan sheets, right-clicking, and choosing Etransmit... .
In the Files Tree tab, each drawing is listed under the Sheet Drawings section, and when expanded, each of them contains the relevant STB plot style:

The settings are out-of-the-box, as far as I recall, but here's a screenshot of my Transmittal Setup anyway, for reference:

Perhaps @dbroad's suggestion that the page setups might not be pointing to the right plot style or that the plot styles may be missing is something to reconsider?
You may also want to ensure that all of the AutoCAD 2017 and AutoCAD Architecture 2017 updates are installed (check the Autodesk Desktop App or your Autodesk Account for updates). Barring this, you could try repairing the software, if you think this is a glitch that started occurring suddenly, when previously it had been working just fine, and nothing else in your environment has changed.
If one or more of these posts helped answer your question, please click Accept as Solution on the posts that helped you so others in the community can find them easily.