diff --git a/core/util/phone.go b/core/util/phone.go
index 079a30f..cf1571d 100644
--- a/core/util/phone.go
+++ b/core/util/phone.go
@@ -31,7 +31,7 @@ var (
 	ErrCannotParsePhone       = errors.New("cannot parse phone number")
 
 	TrimmedPhoneRegexp = regexp.MustCompile(`\D+`)
-	UndefinedUSCodes   = []string{"1445", "1945", "1840", "1448", "1279", "1839", "1555"}
+	UndefinedUSCodes   = []string{"1445", "1945", "1840", "1448", "1279", "1839", "1555", "1771"}
 )
 
 // FormatNumberForWA forms in the format according to the rules https://faq.whatsapp.com/1294841057948784
diff --git a/core/util/phone_test.go b/core/util/phone_test.go
index 001636c..0c88c62 100644
--- a/core/util/phone_test.go
+++ b/core/util/phone_test.go
@@ -125,6 +125,7 @@ func TestFormatNumberForWA(t *testing.T) {
 		"19452381431":   "+19452381431",
 		"12793006305":   "+12793006305",
 		"15557043340":   "+15557043340",
+		"17712015566":   "+17712015566",
 	}
 
 	for orig, expected := range numbers {