I received an email saying I was invited to the beta, but I couldn’t access Muse.
PS. hard refresh and log-out + in have already been tried 
Hi @anon5848797 - in our authentication system it seems like you have yet to be invited to Muse Chat, not to be confused with Muse Tools (sprite + texture). Really glad you are so eager to get started using Muse Chat, so stay tuned and keep an eye on your email!
Best, Martina
Muse is being replaced with Unity AI and all Muse experimental packages are now sunset. Read more about Unity AI here: Unity AI: AI Game Development Tools & RT3D Software | Unity