40 Domain Name Not Valid New

I am having trouble recieving email and i don t know if this is the cause.
Domain name not valid. Specify a valid domain name and try again appears when setting the domain to domain local in safesync for enterprise ssfe. Invalid domain names are always going to be an underlying issue as at some point or another a member of the public is going to attempt to purchase a domain and either making a typing error or merely not know that the domain will become invalid resulting in an invalid domain name that will receive error messages when inserted into your browser. Hello i have a windows server 2016 essentials server if i want to setup anywhere access i need setup domain too.
Fixing the domain name is not valid error when configuring domains in safesync for enterprise the domain name is not valid. The domain name is not valid i ran the configure internet and email wizard on sbs 2003 which seemed to work fine the mx records for the domain look fine from using mxtoolbox. How can i use my abc group domain.
In set up your domain name panel add my group domain name but it says the domain name is not valid.