I had a Foodora offer, which I believe has now expired due to my not being able to access it the past few days, and a Boston Pizza offer. I have not redeemed any offers recently.
I am also having this issue. I have not had this issue before. I am running the latest version of the app on iOS 12.3.1 on an iPhone XS. It still does not work after force closing the app as well as after deleting and reinstalling it.