The reason this occurs is due to the current functionality and restrictions of the Recommenders feature. It is currently built to only support e-mail addresses in the xxx@yyy.zzz format, e.g.

Some Recommenders may have a three-part email address, e.g., which will cause the error mentioned above to occur. The best way past this is to have your Applicants ask the Recommenders if they may use an alternate e-mail address that uses the xxx@yyy.zzz format instead.

We have created an Idea in our Community Portal, as we hope to improve on the Recommenders feature so that it will allow e-mail addresses in the format of Please log into and vote on the Idea below if you would like to see this feature improved upon in the future: