diff --git a/core/utils.py b/core/utils.py
index 84bf46fe..4ffa90fa 100644
--- a/core/utils.py
+++ b/core/utils.py
@@ -710,7 +710,7 @@ def validate_flexible_url(value):
         # Matches: http://hostname, https://hostname/, http://hostname:port/path/to/file.xml, rtp://192.168.2.1,  rtsp://192.168.178.1, udp://239.0.0.1:1234
         # Also matches FQDNs for rtsp/rtp/udp protocols: rtsp://FQDN/path?query=value
         # Also supports authentication: rtsp://user:pass@hostname/path
-        non_fqdn_pattern = r'^(rts?p|https?|udp)://([a-zA-Z0-9_\-\.]+:[^\s@]+@)?([a-zA-Z0-9]([a-zA-Z0-9\-\.]{0,61}[a-zA-Z0-9])?|[0-9.]+)?(\:[0-9]+)?(/[^\s]*)?$'
+        non_fqdn_pattern = r'^(rts?p|https?|udp)://([a-zA-Z0-9_\-\.]+:[^\s@]+@)?([a-zA-Z0-9]([a-zA-Z0-9_\-\.]{0,61}[a-zA-Z0-9])?|[0-9.]+)?(\:[0-9]+)?(/[^\s]*)?$'
         non_fqdn_match = re.match(non_fqdn_pattern, value)
 
         if non_fqdn_match: