I have the same issue – when I tried to generate a key with version 6.2 it fails every time. I get the infamous “POST callback to?https://drewbusinessbroker.com/wp-json/litespeed/v1/token?failed.” message It is not a REST API issue, or whitelist issue.
If I try to access the URL directly while version 6.2 is installed I get this message:
{"code":"rest_forbidden","message":"Sorry, you are not allowed to do that.","data":{"status":401}}
If I downgrade to version 6.1 of the plugin, and access in the URL I get this message instead:
{"_res":"ok"}
AND I can successfully generate a key. The only difference is it works with the downgraded plugin and not the new version. I am having this issue on several sites, and the only way to use the Litespeed plugin and generate a key is to downgrade to version 6.1
