I have installed InvoicePlane into a directory on a Namecheap hosted domain. The setup process breaks when it comes time to create the user though, always ended up at a 403 forbidden error page when I click submit, regardless of how many or few boxes are filled in.
I’ve been through the other suggestions on the forums that I came across - recreating a new blank database (no change) and manually injecting a user and then resetting the password (it never sends me an email to reset the password). I receive no other errors up to this point (a clean suite of green ticks).
Exact error message: http://prntscr.com/9tqgjp
Logs (SSL): http://pastebin.com/ZkQLEprn (domain redacted)