I updated my email address, that went fine. Wanted to change it back to the old email address and got this error. The email address was set but it threw this error. What can I do about this?

AssemblyVersion: 04.04.01
PortalID: 0
PortalName: Smallbizserver.Net
UserID: 1441
UserName: Mariette.Knap
ActiveTabID: 320
ActiveTabName: Registration
RawURL: /Default.aspx?tabid=320&UserID=1441
AbsoluteURL: /Default.aspx
AbsoluteURLReferrer: https://www.smallbizserver.net/Default.aspx?tabid=320&UserID=1441
UserAgent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)
DefaultDataProvider: DotNetNuke.Data.SqlDataProvider, DotNetNuke.SqlDataProvider
ExceptionGUID: c47cba3d-286d-4c64-9e4a-5831e0824b9e
InnerException: The E-mail supplied is invalid.
FileName:
FileLineNumber: 0
FileColumnNumber: 0
Method: System.Web.Security.SqlMembershipProvider.UpdateUser
StackTrace:
Message: DotNetNuke.Services.Exceptions.PageLoadException: The E-mail supplied is invalid. ---> System.Configuration.Provider.ProviderException: The E-mail supplied is invalid. at System.Web.Security.SqlMembershipProvider.UpdateUser(MembershipUser user) at System.Web.Security.MembershipUser.Update() at DotNetNuke.Security.Membership.AspNetMembershipProvider.UpdateUserMembership(UserInfo user) at DotNetNuke.Security.Membership.AspNetMembershipProvider.UpdateUser(UserInfo user) at DotNetNuke.Entities.Users.UserController.UpdateUser(Int32 portalId, UserInfo objUser) at DotNetNuke.Modules.Admin.Users.User.cmdUpdate_Click(Object sender, EventArgs e) at DotNetNuke.UI.WebControls.CommandButton.RaiseClick(Object sender, EventArgs e) at System.Web.UI.WebControls.LinkButton.OnClick(EventArgs e) at System.Web.UI.WebControls.LinkButton.RaisePostBackEvent(String eventArgument) at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) --- End of inner exception stack trace ---
Source:
Server Name: WEBSERVER