This is because you are connecting to the registeration page using hamachi, juz like u are using hamachi to connect to godms's server. when godms isnt online in hamachi, that means the connect from you to him is lost, thus you are unable to connect to the registeration page.
Right now from what i have heard, godms is trying to make the registeration page open for all without using hamachi. In another word, he is trying to let others connect to the webpage without using hamachi.
* Webpage = Registeration Page