Same here. It seems to be an issue with the domain beammp.com itself. As far as I understood, the admin needs to get a new ssl certificate, since the current issued by cloudflare isn’t trusted anymore. It seems there is not much you can do but wait.
See here for reference:
https://bbs.archlinux.org/viewtopic.php?id=305427
https://bbs.archlinux.org/viewtopic.php?id=305571&p=2