distributed testing- trying to add host gives error invalid address

Please give a more detailed explanation including screenshots.  When you use very few words in a post, we have to spend time guessing what you actually did and that's a waste of everyone's time.  

Hi SanjanaZagade ! Could you provide more details about your case as Marsha is asking? It would be much easier for the Community members to pinpoint your issue then and try providing you with a solution! Thanks.