For those of you who host their own Lemmy instance internally, are you able to log in to your Lemmy account after connecting with the local IP address?
I get SyntaxError: JSON.parse: unexpected character at line 1of the JSON data.
EDIT: I should mention I use OPNSense and when I visit the domain, I'm taken to the router's login page.
I had the same issue as OP when setting up my instance. Properly setting the domain name in all the config files fixed it for me. So I am assuming you are right.