Error 400 - Bad Request

Good morning,

I'm having an issue with an API with Swagger, that connects to an enterprise application, and it is used by a bot to post & get registers from said enterprise applications. The issue is that 50% of the time works fine, and the other 50% it does not, showing an error 400 bad request. I'll add the link as an image since it appears as having invalid HTML. 

We have checked the code of the bot already and did not see an issue, and with the same code and the same inputs from the user, sometimes it works fine and then it appears the error 400. 

Also, when I try to load the Swagger API, sometimes it does not load correctly, displaying the same error code 400 - Bad Request (not as often as the bot).

Thank you for your time and have a nice day!

Pedro