There are a couple of reasons why this might be happening:
- The most common reason for this is that your host is just taking awhile to update your new CNAME. Assuming your CNAME is setup correctly (see point 2 below), give it a couple of hours and it should start working;
- Double-check that your CNAME is pointing to
secure.pageserve.co(How to check if the CNAME record is propagating) and triple-check for any spelling mistakes.
If your CNAME looks right, and you have waited for a couple of hours for it to update, contact your registrar to ask why the CNAME is not propagated yet if it has been set up correctly.