[Google Chat] Getting "Server error occurred. Please try again." despite message created.

[nurhun]

I'm creating simple chatbot using go-client lib to create and update cards.

However, I'm able to create the message, I'm getting "Server error occurred. Please try again." OR "

 unable to process your request." errors as shown here https://imgur.com/a/Ba3CQtU

Any idea, why this happens ?