Re: Registering vSphere Replication Appliance with VCSA failing with

I will recommend below to resolve lookup and SSL certificate issue:

Note: vCenter Server generates new default certificates using this option. For systems that use custom certificates, regenerate the certificates manually.

1. Login into vCenter VA Configuration https://[hostname]:5480

2. Select the Admin tab

3. Click Toggle certificate setting, you will see Certificate regeneration enabled change to Yes.
Image may be NSFW.
Clik here to view.

4. Re-boot the Virtual Appliance

5. After the vCenter Server Appliance restarts, confirm that the Certificate regeneration enabled option is set to disable.