Hi Robert,
please, try to use this service as FeatureLayer with the last 3.x API
http://geo.serfor.gob.pe:80/geoservicios/rest/services/Prueba/MapServer/4
Im loading an very easy webpage only with a Map and one Service. If a load the page from localhost or from LAN-IP make not a difference.
I would be happy with a client side solution for this issue.
Best Regards,
Cesar Revilla
Update: Thank you Robert, it was the same behavior as in 4.x API. (I think it had another problem with my test with the LAN-IP).
With an IP or with mache name works perfect. From Localhost or from 127.0.0.1 (Localhost-IP) uses the API HTTPS instead HTTP.
solved!