We're using B2evolution on an intranet, and other pages on the intranet use URLs starting with http://intranet/, not a fully qualified domain name (FQDN).
When one of our bloggers tries to include a link to another intranet page, they get an error message complaining about "invalid URL format".
General Support
b2evolution CMS Support Forums
I'm on version 3.3.3, by the way