It should be right. You have set as priority 5. I have set 1. Maybe that?
Are you using for your domain your i-MSCP server as nameserver or an external nameserver? When you are using an external nameserver you need to set the SRV record there.
When you change something in DNS zone files it could take some hours till the records are working.
BTW: SRV Records aren't working in Minecraft when running on Mac OS X. Maybe you have a Mac?