Users can't create account

Hello please i dont know want is wrong with my site, users can't register from the pro-site frontpage form anymore. and is not working is showing this page have been deleted. here is the link to just try to see if you can create site and see what i mean.

another issue is that i created affiliate page but the content is not displaying what is in the the backend post. is not updating in real time befor but is it seems like is the catche plugin that delayed it. do actually need to disable the plugin when am working on the site? but this is a maltisite other users also working on the site a user complain about this! please and check all this access is granted already. thanks