There are various cases where a domain name MAY NOT be transferable to another Registrar. This could happen in the following circumstances:
(a) Domain Name is less than 60 days Old - If the domain you are trying to transfer is less than 60 days old, the request will get rejected by the Registry itself. Domain names less than 60 days old are not allowed to be transferred to any other registrar by ICANN Guidelines
(b) Domain Name has been transferred less than 60 days ago - If you have transferred your domain name to less than 60 days back, then it can not be transferred again for a period of 60 days. An exception to this rule is the transfer back to the previous Registrar in cases where both Registrars so agree and/or where a decision in the dispute resolution process so directs.
(c) You have Locked your Domain Name - If you have Locked your domain name from the Control Panel provided by the current Registrar, then a Transfer Request for that domain name will not be allowed. You will first have to unlock the Name from the Control Panel and then proceed with a Transfer Request.
(d) Your Registrar has applied a Lock or Hold on your Domain Name - If the current Registrar has applied a Lock or Hold on the domain name due to some pending issue, you would be advised to get in touch with their (current Registrar's) Support Team to resolve this issue, before applying for a transfer.
(e) If the domain name is in Redemption Period or in the Pending Delete State, the domain name can not be transferred.