Transfer domain from Route 53 domain to another registrar - Problems: The domain is not transferable at this time

The error message you're encountering suggests there might be an issue with the authorization code or the transfer process for your domain. Since you've confirmed that the transfer lock is off, the domain wasn't recently registered, and the domain status is OK, there are a few potential solutions to try:

1. For Route 53 domain transfers, you may need to contact AWS Support directly. Even if you're on a Basic Support plan (which typically doesn't include technical support), AWS provides free assistance specifically for domain registration issues, including transferring domains from Route 53.

2. To get support, you should create a case under "Account and Billing" with the category "Domain Registration Issue." This doesn't require a paid support plan and is specifically designed to help with domain transfer problems.

3. In some cases, the authorization code provided by Route 53 might need to be regenerated. AWS Support can help verify the validity of your current auth code or generate a new one if needed.

4. Some domain extensions (like .au domains) can have specific transfer requirements that might cause this error, though this seems less likely in your case since you mentioned the domain has been registered since 2007.

Creating a support case is likely your best option to resolve this issue, as they can investigate the specific reason for the transfer block and help you complete the transfer process.
Sources
Route 53 domain transfer out - auth code is not valid | AWS re:Post
Could not transfer .au domain out from Route 53 | AWS re:Post
Route 53 Domain transfers to another registrar | AWS re:Post