## Answer Please call the API after starting the "Web Service" by following the steps below. --- ## Overview Due to .NET specifications, the Pleasanter API becomes operational once the Web Service starts, which is triggered by the first accepted request. Immediately after Pleasanter starts (e.g., via systemctl start pleasanter or an IIS restart), the Web Service has not yet launched until a request is received. As a result, attempting to call the API before that point will result in an error. To start Pleasanter as a Web Service, perform one of the following steps: 1. Access any page such as the Login page at least once. 2. Use the [Health Check feature](/manual/health-check). The [Health Check feature](/manual/health-check) is available in Pleasanter Version 1.4.8.0 and later.