Hi all,
Thanks @frogerme for your response! I figured out what the issue is (and it came from my own lack of understanding of the way this plugin and browsers in general work). Everything now works.
For anyone else who may encounter something similar and not be super tech savvy, to make sure the login from site A carries over to site B, you have to link directly from site A to site B so that the login (cookie?) is preserved. It WON’T work if you open a new browser window or a different browser and type in the other site.
So, the use case looks like:
Login to site A, click link on site A that takes you to site B (and you are logged in).
OR
Login to site B, click link on site B that takes you to site A (and you are logged in).
Logout works from either site. You can open other site in a new window as long as the tab is opened from the first site.
Thanks for this plugin!