在CloudFlare添加的加速域名后，点击SSL证书一栏提示说CAA错误，颁发证书失败。主要原因是我在之前已经给域名添加了CAA，只不过只限于:letsencrypt.org，直接导致了CloudFlare无法给域名颁发新的证书。

解决办法也比较简单，就是增加CloudFlare的CA即可，设置如下：

example.com. IN CAA 0 issue "letsencrypt.org"
example.com. IN CAA 0 issue "comodoca.com"
example.com. IN CAA 0 issue "digicert.com"
example.com. IN CAA 0 issue "globalsign.com"
example.com. IN CAA 0 issuewild "comodoca.com"
example.com. IN CAA 0 issuewild "digicert.com"
example.com. IN CAA 0 issuewild "globalsign.com"
example.com. IN CAA 0 issuewild "letsencrypt.org"