From reseller's CP when you click on "access to admin section" the following message is shown:
"You have entered invalid control panel location. Please enter your account login and password"
Wrong DNS settings
Check that Reseller's CP link resolves to the correct IP address
# nslookup r13272.res.domain.tld Server: 126.96.36.199 Address: 188.8.131.52#53 Non-authoritative answer: Name: r13272.res.domain.tld Address: 10.10.10.10
Where address 10.10.10.10 is IP address of your CP server.