Issue
I was trying to update my Appsmith instance from version 1.7.14 to 1.9.7, but kept getting a 503 error. Upon checking the logs, I found a failure in Mongock that was related to bad padding in the encryption password. However, I verified that there were no extra spaces in the configuration file. I tried updating to the checkpoint version 1.9.2 first, but still faced the same issue. I am using Ubuntu 20.04.3 LTS with Docker. I was finally able to fix the issue by updating slowly, first to version 1.8.1, then to 1.8.10, then to 1.8.15, then to 1.9.1, and finally to the current version 1.9.12. It seems that the missing step was migrating to version 1.9.1.
Resolution
The user was trying to update their self-hosted Appsmith instance from version 1.7.14 to 1.9.7, but encountered a 503 server unavailable error during the update. The logs showed a cipher failure, indicating an issue with the encryption password or salt. However, the user did not backup/recover their data and was only migrating to new versions.
After several attempts to update directly to 1.9.2, the user slowly migrated to earlier versions (1.8.1, 1.8.10, 1.8.15, and 1.9.1) first. They tested each version before moving on, and found that updating to 1.9.1 was an important step that was missing from their initial update.
The user was able to complete the update to the latest version (1.9.12) successfully. To help other users in a similar situation, Appsmith support requested the logs from the migration to 1.9.1 and 1.9.2, which the user sent. If there are concerns about confidential data in the logs, it is recommended to send them privately to Appsmith support instead of posting them publicly.