diff --git a/main.go b/main.go
index 93bcd12..2f8af40 100644
--- a/main.go
+++ b/main.go
@@ -29,7 +29,7 @@ type TokenCache struct {
 }
 
 func (c *TokenCache) Credentials() (*google.Credentials, error) {
-	if c.CredentialData != nil {
+	if c.CredentialData == nil {
 		f, err := os.Open(c.CredentialPath)
 		if err != nil {
 			return nil, fmt.Errorf("could not open credentials: %v", err)