diff --git a/oauth2.go b/oauth2.go
index 739e73b..ec657a1 100644
--- a/oauth2.go
+++ b/oauth2.go
@@ -289,7 +289,8 @@ func providerAuthHeaderWorks(tokenURL string) bool {
 	if strings.HasPrefix(tokenURL, "https://accounts.google.com/") ||
 		strings.HasPrefix(tokenURL, "https://github.com/") ||
 		strings.HasPrefix(tokenURL, "https://api.instagram.com/") ||
-		strings.HasPrefix(tokenURL, "https://www.douban.com/") {
+		strings.HasPrefix(tokenURL, "https://www.douban.com/") ||
+		strings.HasPrefix(tokenURL, "https://api.dropbox.com/") {
 		// Some sites fail to implement the OAuth2 spec fully.
 		return false
 	}