For about a month now, Apple's official forum has been filled with reports from dissatisfied customers. According to these reports, content from the Apple TV+ app rated 16+ cannot be streamed. This only appears to affect MacBook models, regardless of the model. Users of iPhones, iPads and streaming box users are not affected.
Operating system prevents app verification
The origin of the bug is not yet clear, but some users suspect that it appears to have been caused by the Macbook OS Sequoia 15.4 update. Specifically, the operating system prevents the app from being verified. This suspicion is strengthened by the fact that all content can be streamed if Apple TV Plus is accessed via the web browser and not via the app.
Other devices, such as iPhones, iPads, or TV sets do not appear to be affected. No other measures, such as disabling age verification in the settings or logging out and back in again, seem to help. Apple is yet to provide an update on the matter.