In your router there is a reference to a site that converts Internet names to Internet numbers. It can also default to you Internet supplier. Try substituting the following ip numbers for
www.mobileread.com, 138.201.168.226
If this works then the ip is not blocked by the translation may be missing the MobileRead site. You may be able to change the location you use for translation of the name to numbers in your router or you can complain to your provider.
Dale