Make sure your domain name is unlocked on your previous registrar, because the lock was made for protection from these kinds of action.

Domain Name Authorization Code or EPP.

Some registrars take 3 to 5 days to send the authorization code for your domain name, but others might send it to you within the same minute.

Make sure you get the code, because this is the “Password” needed for the transfer process.

Be sure to remove any privacy related subscriptions on your domain name, because if your data is not visible on WHOIS, your domain name cannot be transferred anywhere.

Transferring domains that are younger than 60 days is usually impossible, so make sure your domain has lived quite a while out there before you consider transferring it out.

There are some common bugs which often happens on the initial registrar that you should take into consideration before initiating the transfer, because all of them could be a reason to halt the process:

• Domain Lock might take some time to unlock your domain before you can transfer, even though it might show as unlocked. If any trouble persists later on, you could always re-lock and unlock to make sure you avoided any passive reasons.
• Privacy settings and shields might behave the same way, but the difference the WHOIS update propagation takes more than few minutes to do so (estimated between 2-6 hours). In some cases the propagation is quick and the process can be initiated within 30 mins or less, but that is very rare and specific. If the process is still at halt after a while, re-applying privacy and removing it might as well solve a lot of troubleshooting.

By Default all the domain name information and DNS records should be transferred during the transition without any manual interventions. However, sometimes In some rare cases, the system is unable to read the NS (Name Servers) and DNS records, and so it does not copy them.

So it is always a good idea to keep a copy of the records before initiating the transfer process.