Automatic SSL for multitenant Saas

I have an ubuntu server with openresty which uses lua-resty-auto-ssl to auto generate SSL and then nginx to reverse proxy to our app but it´s giving me a "too many redirects" error. I need someone who can help us debug and fix the error. The use case is we have a Saas providing whitelabel to our customers. Customer A can point [login to view URL] to a cname and get a ssl certificate and use our app whitelabeled. It was working correctly, but suddenly it is giving us the redirection error.