While configuring Checklist tasks, External URL is not working

Summary

While configuring Checklist tasks, External URL is not working

Content

1) While configuring a checklist, we have used action type External URL and provided onedrive link for file location. But the link is not redirecting correctly from notification.

Even the instance URL is not working getting 403 error. Could you please advice how can we achieve this.

2) Also i would like to know if we can customize description field in checklist task using personalization i.e. to make bold.

3) Significance of Notes tab in checklist task.

Thanks,

Sairam