Content-Security-Policy (CSP) is a browser feature that limits what origins (i.e. domains) your page can interact with. When you configure a security policy on your website, the browser will reject any connections that don't fit the policy. If you're using the <script> tag to inject Service Bell into your site, it's likely you may not have added the Service Bell domains to your policy.
To use Service Bell with a CSP, add the following directives only if you've already specified them for your other resources: