Ace the Google Cloud Certified Associate Engineer Exam 2026 – Skyrocket Your Cloud Skills!

A Google Cloud Pub/Sub subscription may not receive messages from a topic because the subscription has been configured with an acknowledgment deadline that is shorter than the time needed to process the incoming messages. This means that the subscription automatically acknowledges receiving a message before the application has finished processing it, leading to the message being lost. The other options are incorrect because

A: This option refers to IAM permissions, which are not related to the communication between topic and subscription.

B: This option suggests that the encryption used by the topic and subscription are not compatible, but this would result in an error message rather than a loss of messages.

C: Network connectivity issues can affect communication between topic and subscription, but in this case, messages would still be received by the subscription, just at a slower rate or with potential delays.

Therefore, the correct option is D, as a mismatch in the acknowledgment deadline and message processing time can lead to a subscription not receiving messages from a topic.