diff --git a/internal/internal.go b/internal/internal.go
index 7222bfe..f66bde5 100644
--- a/internal/internal.go
+++ b/internal/internal.go
@@ -48,6 +48,11 @@ type AppConfiguration struct {
 
 func (a *App) FixUsername(username string) string {
 	if !strings.HasSuffix(username, a.userSuffix) {
+		// Only add a @ if the configured user suffix doesn't already
+		// start with one.
+		if strings.HasPrefix("@", a.userSuffix) {
+			return fmt.Sprintf("%s%s", username, a.userSuffix)
+		}
 		return fmt.Sprintf("%s@%s", username, a.userSuffix)
 	}
 	return username