I hear that Gmail has recently started objecting to more mail from non-Gmail senders than usual.
So if you use Gmail, it might be a good idea to keep a closer eye than usual on your spam folder. (And mark non-spam as non-spam.)
And if you don’t use Gmail, and you’re waiting an unusually long time for a response to something that you sent to a Gmail user, it might be worth contacting them via other channels to make sure the mail reached them.
