diff --git a/fluxc/src/main/java/org/wordpress/android/fluxc/utils/MimeTypes.kt b/fluxc/src/main/java/org/wordpress/android/fluxc/utils/MimeTypes.kt
index 551e8142c4..d049b36a26 100644
--- a/fluxc/src/main/java/org/wordpress/android/fluxc/utils/MimeTypes.kt
+++ b/fluxc/src/main/java/org/wordpress/android/fluxc/utils/MimeTypes.kt
@@ -232,7 +232,7 @@ class MimeTypes {
         return expected.any { mimeType -> mimeType.subtypes.any { print(mimeType.type, it) == type } }
     }
 
-    fun getMimeTypeForExtension(extension: String): String? {
+    fun getMimeTypeForExtension(extension: String?): String? {
         return (imageTypes + videoTypes + audioTypes + documentTypes).find { it.extensions.contains(extension) }
                 ?.toString()
     }