This issue is usually reproduced on heavier websites — sites with a large amount of content, pages or media take longer to migrate, which can trigger several timeout-related problems described below. Migration preparation step takes too long The migration process starts from the preparation step, which is executed within a single web request in the builder. For heavier websites, this step can take a few minutes, and sometimes even 10+ minutes to complete. To fix it: increase the web server (Apache or nginx) timeout on the builder server. MySQL connection closes during migration Since the preparation step runs as one long web request, MySQL may close the connection before it finishes. To fix it: increase the MySQL timeout values: wait_timeoutinteractive_timeout Migration fails after exactly 30 minutes By default, the migration preparation step has a default timeout of 30 minutes. If the error occurs during migration after exactly 30 minutes, it means this default timeout is not enough for your website. To fix it: Open the config.json file of your builder.Add the parameter "temporaryPublishTimeout" and set its value to 7200 (1 hour).Repeat this change in the v3/config.json file as well, since the same parameter needs to be set there too.