nameserver300.coolcom.com has no SRV records.
Question and response
Question
dig nameserver300.coolcom.com. SRV
Answer
The response has no answer records.
Authority
nameserver300.coolcom.com. 86400 SOA ns7.coolcom.com. root.nameserver300.coolcom.com. 2024090400 3600 1800 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0