diff --git a/src/Validators/CallValidator.php b/src/Validators/CallValidator.php
index f7a83e4..aed5f6c 100644
--- a/src/Validators/CallValidator.php
+++ b/src/Validators/CallValidator.php
@@ -29,7 +29,7 @@ class CallValidator
         if (!is_array($value)) {
             return false;
         }
-        if (isset($value['from']) && AddressValidator::validate($value['from']) === false) {
+        if (isset($value['from']) && AddressValidator::validate($value['from']) === false && $value['from'] !== '') {
             return false;
         }
         if (!isset($value['to'])) {