The Circle team is aware of a serious incompatibility issue with Circle and the first generation of Eero routers (we don't believe this affects the second generation).
Devices are not able to reach the Internet on profiles set to a Filter level of "Adult" or below on Eero networks. Devices on a Filter level of "None" or set to "Unmanaged" are able to reach the Internet.
An Eero software update to first generation units, released in the Fall of 2017, seems to have caused this issue. The Circle team has determined that the root cause lies with Eero's handling of network traffic since this update, and is not resolvable by a firmware update to Circle.
At this time, there is no workaround, other than switching all profiles to a "None" filter level, or connecting Circle to a different compatible router.
Those affected should reach out to Eero support for further troubleshooting.