As the project is working properly on some environment, the issue appears to be caused by server specific issue that is either web config setting of the environment where the site is running.
Another possible cause for this issue could be some server configuration which prevents your project from functioning, so please check if the IIS server is configured covering all points from this
If the server is configured correctly then make sure in IIS there are no add-on modules that intercept web service requests or perform additional functionality on the site, to also move them out of the equation for the problem can you temporary disable those and check your hosted project behavior.
If none of the above helps, you could open a support ticket to further investigate the problem
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