Xy Logan

Hello, I’m trying to import a key sent to me as an attachment, as asc file, but in Thunderbird/Enigmail the asc attachment’s “Import OpenPGP Key” option is greyed. I’ve imported a key successfully before, but not an encrypted one. None of my attempts to decrypt it so far will work. (Apologies, this is close to other posts I have read here, but not the same, and I can’t find my issue addressed anywhere online. I’m aware that it may be a stupid beginner mistake.) I’m running Windows 10 / Enigmail version...