It seems Apple’s iCloud Private Relay, a service that essentially hides your web traffic from your carrier, has been reported as being blocked by T-Mobile for some customers. However, the truth is a little more complex.
According to internal documents shared with us here at The T-Mo Report, the blocking of Apple’s privacy-focused service is actually due to a conflict with existing content filtering services on T-Mobile.
The internal note, which is shared below, states that certain customers with content filtering and blocking features, like T-Mobile’s Web Guard, will be unable to use the iCloud Private Relay feature.
It also states customers on T-Mobile’s Home Office Internet are likely impacted as well due to the built-in website filtering on that plan.
This seems to indicate that the blocking isn’t actually intentional by the carrier, but merely a necessary step to ensure their own services work properly. The blocking affects very few customers in practice, and it seems that there are currently no plans to expand the blocking of Apple’s service to standard customers.
Impacted customers will receive one of two error messages, shown below (sourced from the same internal document), stating that their plan isn’t compatible with the iCloud Private Relay service.
Notice seen by cell plans 
Notice seen by IoT plans (Home Office Internet)
Apple’s iCloud Private Relay was first announced back in June during WWDC. It encrypts and hides your DNS requests and IP address from destination websites as well as your ISP (in this case the carrier, T-Mobile). It was shipped as part of iOS 15, but is disabled by default as a “beta” feature. At the time, some carriers in the EU, including T-Mobile, voiced concerns about losing vital metadata that was supposedly critical to network management.
Sources say that, as far as they can tell, this is the only blocking T-Mobile is doing of Apple’s iCloud Private Relay service (at least in the US). Most customers should have no issues using the feature on their devices, and if they do, they can likely reach out to support to have whatever conflicting feature is active removed from their plan.
