Bad host/IP: youtube.com in youtube.com flags=0 (-2) Name or service not known

after configured acl rule to block specific sites then reload the squid service i got below message.

# service squid reload
2017/10/11 06:03:20| aclIpParseIpData: Bad host/IP: ' .youtube.com'  in ' .youtube.com' , flags=0 : (-2) Name or service not known
FATAL: Bungled squid.conf line 63: acl access dst " /etc/squid/access.txt" 
Squid Cache (Version 3.1.23): Terminated abnormally.
CPU Usage: 0.009 seconds = 0.005 user + 0.004 sys
Maximum Resident Size: 23568 KB
Page faults with physical i/o: 0