Apologies for the inconvenience.
Please enable Debug Mode in Joomla so we can gather more details about the error. To do this, you need to access the Global Configuration settings from the Joomla administrator panel. Under the Server tab, you will find an option called Debug System. Setting this to Yes and saving the changes will activate debug mode, which will provide more information about the issue.
Once Debug Mode is enabled, please try replicating the error and capture a screenshot of the detailed error message. Additionally, kindly share the template name, SP Page Builder version, and Joomla version you are using. This information will help in identifying the root cause of the issue and providing an appropriate solution.