I had been added to a send board where we were able to have our email account coming into our board so everything is centralised. This worked and I would open a card and have the option of clicking the Red Email Button to respond to emails. And now it has disappeared - I have checked that the power up is still working, have refreshed the pages, have move the card back to a board that had previously allowed me to send emails but all to no avail.
Has anyone else had this issue and knows how to resolve?