diff --git a/packages/better-auth/src/plugins/mcp/authorize.ts b/packages/better-auth/src/plugins/mcp/authorize.ts
index e876346aad..732057c4cb 100644
--- a/packages/better-auth/src/plugins/mcp/authorize.ts
+++ b/packages/better-auth/src/plugins/mcp/authorize.ts
@@ -10,7 +10,7 @@ import type {
 } from "../oidc-provider/types";
 
 function redirectErrorURL(url: string, error: string, description: string) {
-	return `${
+	return `${url}${
 		url.includes("?") ? "&" : "?"
 	}error=${error}&error_description=${description}`;
 }
diff --git a/packages/better-auth/src/plugins/oidc-provider/authorize.ts b/packages/better-auth/src/plugins/oidc-provider/authorize.ts
index 77b1f314b8..e3f14af468 100644
--- a/packages/better-auth/src/plugins/oidc-provider/authorize.ts
+++ b/packages/better-auth/src/plugins/oidc-provider/authorize.ts
@@ -7,7 +7,7 @@ import type { AuthorizationQuery, OIDCOptions } from "./types";
 import { parsePrompt } from "./utils/prompt";
 
 function formatErrorURL(url: string, error: string, description: string) {
-	return `${
+	return `${url}${
 		url.includes("?") ? "&" : "?"
 	}error=${error}&error_description=${description}`;
 }
diff --git a/packages/sso/src/oidc.test.ts b/packages/sso/src/oidc.test.ts
index 0596ab1f62..f8caec02f8 100644
--- a/packages/sso/src/oidc.test.ts
+++ b/packages/sso/src/oidc.test.ts
@@ -505,9 +505,7 @@ describe("SSO disable implicit sign in", async () => {
 			"redirect_uri=http%3A%2F%2Flocalhost%3A3000%2Fapi%2Fauth%2Fsso%2Fcallback%2Ftest",
 		);
 		const { callbackURL } = await simulateOAuthFlow(res.url, headers);
-		expect(callbackURL).toContain(
-			"/api/auth/error/error?error=signup disabled",
-		);
+		expect(callbackURL).toContain("/api/auth/error?error=signup disabled");
 	});
 
 	it("should create user with SSO provider when sign ups are disabled but sign up is requested", async () => {
diff --git a/packages/sso/src/routes/sso.ts b/packages/sso/src/routes/sso.ts
index 98b901dd53..c725d8146d 100644
--- a/packages/sso/src/routes/sso.ts
+++ b/packages/sso/src/routes/sso.ts
@@ -1467,7 +1467,7 @@ export const callbackSSO = (options?: SSOOptions) => {
 				throw ctx.redirect(
 					`${
 						errorURL || callbackURL
-					}/error?error=invalid_provider&error_description=provider not found`,
+					}?error=invalid_provider&error_description=provider not found`,
 				);
 			}
 
@@ -1486,7 +1486,7 @@ export const callbackSSO = (options?: SSOOptions) => {
 				throw ctx.redirect(
 					`${
 						errorURL || callbackURL
-					}/error?error=invalid_provider&error_description=provider not found`,
+					}?error=invalid_provider&error_description=provider not found`,
 				);
 			}
 
@@ -1513,7 +1513,7 @@ export const callbackSSO = (options?: SSOOptions) => {
 				throw ctx.redirect(
 					`${
 						errorURL || callbackURL
-					}/error?error=invalid_provider&error_description=token_endpoint_not_found`,
+					}?error=invalid_provider&error_description=token_endpoint_not_found`,
 				);
 			}
 
@@ -1544,7 +1544,7 @@ export const callbackSSO = (options?: SSOOptions) => {
 				throw ctx.redirect(
 					`${
 						errorURL || callbackURL
-					}/error?error=invalid_provider&error_description=token_response_not_found`,
+					}?error=invalid_provider&error_description=token_response_not_found`,
 				);
 			}
 			let userInfo: {
@@ -1561,7 +1561,7 @@ export const callbackSSO = (options?: SSOOptions) => {
 					throw ctx.redirect(
 						`${
 							errorURL || callbackURL
-						}/error?error=invalid_provider&error_description=jwks_endpoint_not_found`,
+						}?error=invalid_provider&error_description=jwks_endpoint_not_found`,
 					);
 				}
 				const verified = await validateToken(
@@ -1575,14 +1575,14 @@ export const callbackSSO = (options?: SSOOptions) => {
 					throw ctx.redirect(
 						`${
 							errorURL || callbackURL
-						}/error?error=invalid_provider&error_description=token_not_verified`,
+						}?error=invalid_provider&error_description=token_not_verified`,
 					);
 				}
 				if (verified.payload.iss !== provider.issuer) {
 					throw ctx.redirect(
 						`${
 							errorURL || callbackURL
-						}/error?error=invalid_provider&error_description=issuer_mismatch`,
+						}?error=invalid_provider&error_description=issuer_mismatch`,
 					);
 				}
 
@@ -1615,7 +1615,7 @@ export const callbackSSO = (options?: SSOOptions) => {
 					throw ctx.redirect(
 						`${
 							errorURL || callbackURL
-						}/error?error=invalid_provider&error_description=user_info_endpoint_not_found`,
+						}?error=invalid_provider&error_description=user_info_endpoint_not_found`,
 					);
 				}
 				const userInfoResponse = await betterFetch<{
@@ -1633,7 +1633,7 @@ export const callbackSSO = (options?: SSOOptions) => {
 					throw ctx.redirect(
 						`${
 							errorURL || callbackURL
-						}/error?error=invalid_provider&error_description=${
+						}?error=invalid_provider&error_description=${
 							userInfoResponse.error.message
 						}`,
 					);
@@ -1645,7 +1645,7 @@ export const callbackSSO = (options?: SSOOptions) => {
 				throw ctx.redirect(
 					`${
 						errorURL || callbackURL
-					}/error?error=invalid_provider&error_description=missing_user_info`,
+					}?error=invalid_provider&error_description=missing_user_info`,
 				);
 			}
 			const isTrustedProvider =
@@ -1679,9 +1679,7 @@ export const callbackSSO = (options?: SSOOptions) => {
 				isTrustedProvider,
 			});
 			if (linked.error) {
-				throw ctx.redirect(
-					`${errorURL || callbackURL}/error?error=${linked.error}`,
-				);
+				throw ctx.redirect(`${errorURL || callbackURL}?error=${linked.error}`);
 			}
 			const { session, user } = linked.data!;