There could be a case when you get the error: Request failed: bad request (400) "The application is disabled due to API calls limit violations. If you are an app developer, please, contact Tech Support via firstname.lastname@example.org"
If you receive this error, please check the following points:
1. The error "bad request (400)" may be caused by a missing or invalid parameter. Please make sure that the request is correct.
2. Also, the issue may be related to the exceeding of API calls limit which means that you have some active users who generate the number of API calls that exceeds the limit of your current plan. Feel free to check this article: https://help.quickblox.com/article/378-what-do-i-do-if-i-receive-an-api-call-rate-limit-has-been-exceeded-email