One of the best: Indie Christian Authors Group on Facebook
If you are looking for a community of authors, closed to keep out scammers, Indie Christian Authors is an excellent group to join. It’s led by a speculative fiction author, Vicki Lucas, with great help administering by Elaine H. Baldwin, Jessiqua Wittman, Nat Davis, and Jansina Grossman. There are over a 1000 members now and you’ll get good support there. No advertising is allowed except for special events (like what is going on now to celebrate going over 1000 members).
Join Indie Christian Authors today if you are an author looking for a warm, helpful community.