moving hosted site to another reseller account

[privatne]

hello,
i have whm reseller hosting account and some sites hosted in. since the provider had many downtimes, i subscribed to another reseller account. now how can i smoothly transfer the hosted sites? i created the new site in the new whm hosting. then i terminated the same site (and did not check keep dns) in the old whm. The account was successfully closed. but now i am getting the error message from internet explorer:
We can not find "www.mydomain.com". The ftp access does not work with dns name (ftp.mydomain.com), but does work with IP address (255.255.255.255).
shall i only wait till dns propagates? do i need to resubmit my dns somehow? please help. thank you.
ps. i made a full backup of the site on the old cpanel and transferred to my pc.

[adept2003]

If you've changed the nameservers on the domain (which is likely), then you will have to wait for the DNS to propagate.

[privatne]

thank you for your prompt reply. well, both resellers offered me private dns, and both whm accounts are set for the same domain. i only had to point my private dns to new ip addresses with the new reseller (which i did cca two days before starting to terminate the old accounts in whm). thus in fact i did not change dns, because the sites are registered with my private dns. how does the situation look now?
also, generally do i move the sites properly (terminate account in whm and so on)?
many thanks.

[adept2003]

So you changed the IP of your nameservers 2 days ago? Doesn't look like a propagation issue... so you'd better check your domain with dnsreport.com

In terms of moving the sites, I would suggest that you do a full backup and download them, just in case. If you can modify the DNS TTL, then I'd set it as low as poss. Copy the acct's across using the "copy multiple acct" feature in WHM. As soon as they're across, modify the DNS IP entry on the old server to point to the new server, to minimise downtime. Once you're happy everything is working okay, delete the old accounts from the old server.

I think thats about it. You may need some help from your new host, in case there are some differences in the server config from the old server (eg. MySQL version, php settings, etc).