Error in Fetching API through SAP UI5 - CORS Error - preflightmissingalloworiginheader

[#1]

onUpdateCaseDetails: function () {
            var sIncidentType1 = "Akash123";
            var sCaseID = "UHEALTH-INVESTIG-WORK I-61005";
            var sActionID = "pyUpdateCaseDetails";
            var sUrl = "https://leaseplan01.pegalabs.io/prweb/api/application/v2/cases/" +
                encodeURIComponent(sCaseID) +
                "/actions/" +
                encodeURIComponent(sActionID) +
                "?viewType=form";

            var sBearerToken = "XXXXXXXXX"; // your full token

            var oPayload = {
                content: {
                    IncidentType: sIncidentType1
                }
            };

            $.ajax({
                url: sUrl,
                method: "PATCH",
                contentType: "application/json",
                data: JSON.stringify(oPayload),
                headers: {
                    "Authorization": "Bearer " + sBearerToken,
                    "If-Match": "20250820T072129.183 GMT",
                    "x-origin-channel": "Web",
                    "Content-Type": "application/json",
                    "Accept": "application/json"
                    // "Access-Control-Allow-Origin" :"*"
                },
                success: function (oResponse) {
                    MessageToast.show("Case updated successfully!");
                    console.log("Update response:", oResponse);
                },
                error: function (oError) {
                    MessageToast.show("Update failed: " + oError.statusText);
                    console.error("Update error:", oError);
                }
            });
        },

[Marla-Ellinger]

Hi @Akash_Kanyadhara  i think  This is a CORS issue. The browser sends a preflight OPTIONS request for your PATCH with custom headers, and the API response does not include the required CORS headers. You cannot fix this in UI5 code alone. You must either enable CORS on the API or call it through a proxy on BTP.

[Akash_Kanyadhara]

In Server they added my URL but i still face this issue