403 errors are most common when placing a new container on the page. If the container is empty a 403 error may be thrown. To keep testing the page without removing the container you can simply add an empty tag to the container.
A Tag Is Not Firing
If a tag is not firing the first thing to check is the setup. For a tag to fire it must be:
1. Active, shown by the green circle next to its name.
2. Placed in the container that is on the page.
3. Dependent tags must have fired. If a tag has a set dependency and that tag is disabled the tag will not be able to fire.
4. Able to meet the conditions of any rules assigned to it.
5. If scheduling is enabled the tag must be within the designated schedule