Dunno if it still happens, but occasionally there was a bug that’d result in the server not sending an e-mail out when you levelled up, and sometimes you could rectify that by turning e-mail notifications off and then back on again. Though checking the junk folder does work too.
If you do miss any future e-mails, you can find the full list of them in this thread (or the list of them as they were in Jun 2020).
