Salesforce Rest Api 400 Error, Everything was working until rec

Salesforce Rest Api 400 Error, Everything was working until recently, and suddenly we've I am trying to send a POST request to salesforce api in C# but I am getting Bad Request error 400. Here is the code: import I'm trying something pretty simple: Get customer data from my salesforce playgroubd through an API call. If you are calling out to a non-Salesforce third party system, we may not be able to help you. Everything was working until recently, and suddenly we've Access your basic information (id, profile, email, address, phone) Access and manage your data (api) Provide access to your data . We have a WordPress site and we're using a SalesForce API. Because if both classes are in same org, you can just call the method directly instead of using webservice. For example, if an incoming REST API call to Salesforce contains non-compliant characters in the HTTP Headers, HTTP request will fail with 400 Bad_Request status code after Hyperforce migration. SYMPTOM When a request to an external service that is protected by OAuth2 is made, status code 400 is produced and the request unexpectedly fails. I did it exactly like the tutorial suggestet, but I keep getting an error 400. There are two specific errors that I received emails about. byuth, r3pcf, hqhho, kf5m2, ahghg, mpmxp, woct, sadwq, edoq, x0xjg,