Issue

Mendix Cloud environments enforce a 15-minute startup timeout. If an application fails to initialize within this window, the startup process is terminated. 

Although no explicit error is recorded in the logs, the application will shut down 15 minutes after the startup sequence began:

2026-09-18T13:54:51.057614 [runtime-container/j2gcc]  INFO - M2EE: Runtime server started.

...

2026-09-18T14:09:27.646314 [runtime-container/j2gcc]  INFO - RuntimeWatchdog: Waiting for application to shutdown...
2026-09-18T14:09:27.649292 [runtime-container/j2gcc]  INFO - M2EE: Runtime shutdown requested.
2026-09-18T14:09:27.652564 [runtime-container/j2gcc]  INFO - RuntimeWatchdog: The application has been stopped successfully.

Environment

Applications hosted in Mendix Cloud

Cause

In the Mendix Public Cloud, a readiness check is configured with a time limit of 15 minutes. If the application is not considered ready within these 15 minutes, the runtime will be shut down. 

The reason for reaching the timeout is often one of two things:

• During runtime startup, the database schema is updated with the changes made in the domain model(s). The application will only start after all the synchronization is completed. If there are too many changes the update to the database schema could take longer than the time limit. The database synchronization time is influenced by the following:
  • Amount of changes required
  • The size of the database table to which these changes are applied
• The after-startup microflow is configured to process data. This process cannot be completed within the time limit.

After the timeout, all the activities that were done on the database will be rolled back so there will be no harm done to the data. 

To determine which one of the above two causes the application is experiencing go to the application logs and observe what activity is logged before the timeout log is thrown. When the log indicates database schema changes are applied, it is a problem with too many changes in the domain model(s). As an example, this environment was executing 1335 database synchronization commands when it reached the timeout. 

2026-09-18T07:30:41.977742 [runtime-container/rgb2p] INFO - ConnectionBus: Executing 1335 database synchronization command(s)...
2026-09-18T07:44:25.660979 [runtime-container/rgb2p] "no auth required"
2026-09-18T07:44:25.661100 [runtime-container/rgb2p] "Send signal to program" program=watchdog signal=terminated
2026-09-18T07:44:25.734359 [runtime-container/rgb2p] "no auth required"
2026-09-18T07:44:25.734438 [runtime-container/rgb2p] "Get process info of: runtime"
2026-09-18T07:44:25.735866 [runtime-container/rgb2p] INFO - RuntimeWatchdog: Waiting for application to shutdown...

When the after-startup microflow is initiated but not ended, it is a problem with the after-startup microflow.

Solution / Workaround

It is advised to not release a lot of domain model changes in a single release but to do them in steps such that the synchronization process will not time out. Also, it is not advised to do data processing in the after-startup microflow.

To manage larger updates, the following workaround is available: For the below explanation, note that the model deployed to the environment is 1.0.0, and now version 2.0.0 needs to be deployed.

1. Stop the environment.
2. Create a backup.
3. Download the backup.
4. Restore the backup locally.
5. Connect it to version 2.0.0 in a local instance of Studio Pro. 
6. Start the app, this will run the synchronization commands to upgrade the database schema locally and run the after-startup microflow.
7. Create a backup from this upgraded database and upload it to the environment.
8. Clear the database of the environment and restore the newly uploaded backup. 
9. Deploy version 2.0.0 to the environment.

As a last resort, Support can disable the readiness check. For more information an inportante considerations regarding this change, see What is the Mendix Cloud Readiness Check. 

Additional information

• Mendix documentation: Runtime Tab After-Startup
• Related KBA: What is the Mendix Cloud Readiness Check