I see that Banestrike (who is coincidentally also in my guild / on my server) had a previous post on this same topic back in May, but since the answer didn't solver her problem (or mine), I'm posting the question again.
When using the mobile app, with my main character selected, when I go to Guild Events, I get the message "This character profile is currently unavailable due to a long period of inactivity."
I get the error no matter which character I use and no matter what I try to do to the app. It worked when I first got the app, but hasn't worked in months.
I access the mobile app logged in as my main, which I play every day.
It's very frustrating not to be able to see guild events, which is the main reason I wanted the mobile app.