diff --git a/core/modules/link/src/Plugin/migrate/process/FieldLink.php b/core/modules/link/src/Plugin/migrate/process/FieldLink.php
index 978f4e9..4d3d7ee 100644
--- a/core/modules/link/src/Plugin/migrate/process/FieldLink.php
+++ b/core/modules/link/src/Plugin/migrate/process/FieldLink.php
@@ -88,11 +88,9 @@ protected function canonicalizeUri($uri) {
       $end = $directories . '?' . $query . '?' . $anchor . '?' . '$/i';
 
       if (!preg_match($internal_pattern . $end, $uri)) {
-        $allowed_protocols = ['http', 'https', 'ftp', 'news', 'nntp', 'telnet', 'mailto', 'irc', 'ssh', 'sftp', 'webcal'];
         $link_domains = '[a-z][a-z0-9-]{1,62}';
 
         // Starting a parenthesis group with (?: means that it is grouped, but is not captured
-        $protocol = '((?:' . implode("|", $allowed_protocols) . '):\/\/)';
         $authentication = "(?:(?:(?:[\w\.\-\+!$&'\(\)*\+,;=" . $link_ichars . "]|%[0-9a-f]{2})+(?::(?:[\w" . $link_ichars . "\.\-\+%!$&'\(\)*\+,;=]|%[0-9a-f]{2})*)?)?@)";
         $domain = '(?:(?:[a-z0-9' . $link_ichars . ']([a-z0-9' . $link_ichars . '\-_\[\]])*)(\.(([a-z0-9' . $link_ichars . '\-_\[\]])+\.)*(' . $link_domains . '|[a-z]{2}))?)';
         $ipv4 = '(?:[0-9]{1,3}(\.[0-9]{1,3}){3})';
@@ -100,7 +98,7 @@ protected function canonicalizeUri($uri) {
         $port = '(?::([0-9]{1,5}))';
 
         // Pattern specific to external links.
-        $external_pattern = '/^' . $protocol . '?' . $authentication . '?(' . $domain . '|' . $ipv4 . '|' . $ipv6 . ' |localhost)' . $port . '?';
+        $external_pattern = '/^' . $authentication . '?(' . $domain . '|' . $ipv4 . '|' . $ipv6 . ' |localhost)' . $port . '?';
         if (preg_match($external_pattern . $end, $uri)) {
           return $this->configuration['uri_scheme'] . $uri;
         }