It sounds like your bot is functioning well when side-loaded but encountering issues during the app validation process. The errors you're seeing might be related to specific validation requirements for Microsoft Teams apps. Here are a few steps you can take to address this issue:
First, ensure that your bot meets all the validation requirements specified by Microsoft Teams. This includes providing a clear description, privacy policy, terms of use, and ensuring that the bot's functionality aligns with the declared capabilities.
Even if you did not specify any bot commands, the validation process might expect certain commands to be defined. Consider adding basic commands such as help or info to provide users with guidance on how to interact with the bot.
Double-check your app's manifest file to ensure that all required fields are correctly filled out. This includes the bot's ID, name, description, and permissions. Make sure that the commands section is either correctly defined or omitted if not needed.
Use the Microsoft Teams App Validator to test your bot and validate the manifest file. This tool can help identify any issues that might be causing the validation errors.
Reference Document-https://learn.microsoft.com/en-us/microsoftteams/overview-of-app-validation