Cloud-hosted build agents not getting authorized after TeamCity update to 2026.2 or later

Symptoms

1. Cloud-hosted build agents are used to run builds. These agents are managed by a non-bundled Cloud Profile plugin. For example, AWS ECS, Azure Integration.
2. TeamCity was updated from version <2026.2 to version >=2026.2.
3. Cloud-hosted build agents are started on demand but do not get automatically authorized.

Cause

The issue is caused by a non-bundled Cloud Profile plugin not included in the build agent image.

If the agent side of the non-bundled Cloud Profile plugin is not included in the build agent image, the agent can't use it to retrieve settings (such as name, authentication token, etc.) from the Cloud Profile. In this case, the agent defaults to the standard startup route and gets unauthorized on its first connection.

Due to Do not send commands and do not process commands results from unauthorized agents, starting with the 2026.2 version of TeamCity, unauthorized agents can't pull the plugin from the server.

Once authorized manually, the server issues the upgrade command. The agent then receives the corresponding plugin from the server, retrieves the settings from the Cloud Profile, and starts working normally.

Resolution

If a non-bundled Cloud Profile plugin is used for cloud agents, the build agent images should be created using the full agent zip file that has all plugins included. It can be downloaded from the TeamCity server (Agents > Install Agent page).