I have found Reddit r/lisp and Freenode #lisp to have great communities these days. They serve as good alternatives to comp.lang.lisp. It wasn't always so but both communities have evolved over the last decade to become more friendly to beginners.

Also some of us here from this forum also hang out at a Freenode channel named #spxy (also accessible via https://app.element.io/#/room/#spxy:matrix.org on Matrix). This is a small computer science and mathematics literature club, so quite relevant to those who are curious about or who work in the intersection of mathematics and programming. Incidentally, many members of this channel are also Lisp programmers.