diff --git a/internal/logic/admin/channel.go b/internal/logic/admin/channel.go
index d4800f5..6a4bd9b 100644
--- a/internal/logic/admin/channel.go
+++ b/internal/logic/admin/channel.go
@@ -664,10 +664,13 @@ func (s *sAdmin) GetProviderDefaultURLs(ctx context.Context, _ *v1.ProviderDefau
 
 // defaultProviderURLs 供应商默认 API 地址
 var defaultProviderURLs = map[int]string{
-	1:  "https://api.openai.com",
-	2:  "https://api.anthropic.com",
-	3:  "https://generativelanguage.googleapis.com",
-	4:  "https://dashscope.aliyuncs.com/compatible-mode",
+	1: "https://api.openai.com",
+	2: "https://api.anthropic.com",
+	3: "https://generativelanguage.googleapis.com",
+	// 阿里云百炼填裸域名：adaptor 会按 relay 模式自行拼 /compatible-mode/v1/...（OpenAI 兼容）、
+	// /apps/anthropic/v1/messages（Claude）、/api/v1/services/aigc/...（图像），
+	// 这里若带上 /compatible-mode 会导致路径重复而 404。
+	4:  "https://dashscope.aliyuncs.com",
 	5:  "https://aip.baidubce.com",
 	6:  "https://hunyuan.tencentcloudapi.com",
 	7:  "https://open.bigmodel.cn",
diff --git a/relay/channel/ali/adaptor.go b/relay/channel/ali/adaptor.go
index 9d7bbfc..3b47fbb 100644
--- a/relay/channel/ali/adaptor.go
+++ b/relay/channel/ali/adaptor.go
@@ -28,7 +28,7 @@ func (a *Adaptor) Init(info *common.RelayInfo) {
 // GetRequestURL 构建上游请求 URL。
 // Claude 协议走 Anthropic 兼容端点，OpenAI 走 compatible-mode 端点，图像生成使用独立端点。
 func (a *Adaptor) GetRequestURL(info *common.RelayInfo) (string, error) {
-	baseURL := strings.TrimSuffix(info.ChannelMeta.BaseURL, "/")
+	baseURL := normalizeBaseURL(info.ChannelMeta.BaseURL)
 
 	switch constant.RelayMode(info.RelayMode) {
 	case constant.RelayModeClaudeMessages:
@@ -161,6 +161,30 @@ func (a *Adaptor) GetChannelName() string {
 
 var _ common.Adaptor = (*Adaptor)(nil)
 
+// normalizeBaseURL 归一化渠道 base URL 为 DashScope 裸域名。
+//
+// adaptor 各端点自行拼接完整路径（compatible-mode / apps/anthropic / api/v1/services），
+// 因此 base 必须是裸域名。但用户手填时有三种常见写法都很自然：
+//
+//	https://dashscope.aliyuncs.com
+//	https://dashscope.aliyuncs.com/compatible-mode        （旧版默认值、控制台文档）
+//	https://dashscope.aliyuncs.com/compatible-mode/v1     （阿里 OpenAI SDK 文档的 base_url）
+//
+// 后两种若直接拼接会产生 /compatible-mode/compatible-mode/v1/... 这类重复路径，
+// DashScope 网关在路由层直接返回 404 且响应体为空，极难定位。
+// 这里统一剥离已知后缀，让三种写法都能正常工作。
+func normalizeBaseURL(raw string) string {
+	base := strings.TrimSuffix(strings.TrimSpace(raw), "/")
+	// 从长到短依次剥离，避免先匹配短后缀导致残留
+	for _, suffix := range []string{"/compatible-mode/v1", "/compatible-mode"} {
+		if strings.HasSuffix(base, suffix) {
+			base = strings.TrimSuffix(base, suffix)
+			break
+		}
+	}
+	return strings.TrimSuffix(base, "/")
+}
+
 // convertClaudeRequest 处理 Claude 入站请求的模型映射。
 func convertClaudeRequest(requestBody []byte, info *common.RelayInfo) (io.Reader, error) {
 	if !info.ChannelMeta.IsModelMapped {
diff --git a/relay/channel/ali/adaptor_test.go b/relay/channel/ali/adaptor_test.go
new file mode 100644
index 0000000..16815b5
--- /dev/null
+++ b/relay/channel/ali/adaptor_test.go
@@ -0,0 +1,49 @@
+package ali
+
+import "testing"
+
+// TestNormalizeBaseURL 验证三种常见 base URL 写法都归一化为同一个裸域名，
+// 防止再次出现 /compatible-mode/compatible-mode/v1/... 重复路径导致上游 404。
+func TestNormalizeBaseURL(t *testing.T) {
+	const want = "https://dashscope.aliyuncs.com"
+
+	cases := []struct {
+		name string
+		in   string
+		want string
+	}{
+		{"裸域名", "https://dashscope.aliyuncs.com", want},
+		{"裸域名带尾斜杠", "https://dashscope.aliyuncs.com/", want},
+		{"带 compatible-mode", "https://dashscope.aliyuncs.com/compatible-mode", want},
+		{"带 compatible-mode 尾斜杠", "https://dashscope.aliyuncs.com/compatible-mode/", want},
+		{"带 compatible-mode/v1（阿里 SDK 文档写法）", "https://dashscope.aliyuncs.com/compatible-mode/v1", want},
+		{"带 compatible-mode/v1 尾斜杠", "https://dashscope.aliyuncs.com/compatible-mode/v1/", want},
+		{"首尾空格", "  https://dashscope.aliyuncs.com/compatible-mode/v1  ", want},
+		{"自定义代理域名保持不变", "https://proxy.example.com/dashscope", "https://proxy.example.com/dashscope"},
+		{"自定义代理域名剥离 compatible-mode", "https://proxy.example.com/compatible-mode/v1", "https://proxy.example.com"},
+		{"空串", "", ""},
+	}
+
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			if got := normalizeBaseURL(c.in); got != c.want {
+				t.Errorf("normalizeBaseURL(%q) = %q, want %q", c.in, got, c.want)
+			}
+		})
+	}
+}
+
+// TestNormalizeBaseURLIdempotent 归一化必须幂等，重复调用不改变结果。
+func TestNormalizeBaseURLIdempotent(t *testing.T) {
+	inputs := []string{
+		"https://dashscope.aliyuncs.com/compatible-mode/v1",
+		"https://dashscope.aliyuncs.com/compatible-mode",
+		"https://dashscope.aliyuncs.com",
+	}
+	for _, in := range inputs {
+		once := normalizeBaseURL(in)
+		if twice := normalizeBaseURL(once); twice != once {
+			t.Errorf("非幂等: %q -> %q -> %q", in, once, twice)
+		}
+	}
+}
diff --git a/relay/channel/openai/adaptor.go b/relay/channel/openai/adaptor.go
index 97c475e..26c2cff 100644
--- a/relay/channel/openai/adaptor.go
+++ b/relay/channel/openai/adaptor.go
@@ -308,7 +308,8 @@ func (a *Adaptor) handleChatNonStreamResponse(ctx context.Context, resp *http.Re
 			upstreamErr.ResponseWritten = true
 			return &common.Usage{}, upstreamErr
 		}
-		return nil, constant.NewUpstreamError(resp.StatusCode, string(body), nil).WithRetryAfter(constant.RetryAfterFromHeader(resp.Header))
+		// 响应体不是标准 OpenAI 错误格式（含空响应体）：附带上游 URL 供日志定位
+		return nil, constant.NewUpstreamErrorFromResponse(resp, body)
 	}
 
 	if info.ChannelMeta.IsModelMapped {
@@ -347,7 +348,8 @@ func (a *Adaptor) handleChatStreamResponse(ctx context.Context, resp *http.Respo
 			upstreamErr.ResponseWritten = true
 			return &common.Usage{}, upstreamErr
 		}
-		return nil, constant.NewUpstreamError(resp.StatusCode, string(body), nil).WithRetryAfter(constant.RetryAfterFromHeader(resp.Header))
+		// 响应体不是标准 OpenAI 错误格式（含空响应体）：附带上游 URL 供日志定位
+		return nil, constant.NewUpstreamErrorFromResponse(resp, body)
 	}
 
 	return StreamHandler(ctx, resp, info, writer)
diff --git a/relay/constant/errors.go b/relay/constant/errors.go
index c33ae93..58b1095 100644
--- a/relay/constant/errors.go
+++ b/relay/constant/errors.go
@@ -30,21 +30,32 @@ type RelayError struct {
 	// RetryAfter 上游 Retry-After 头解析结果（0 = 未携带）。
 	// 调度重试 FSM 据此决定 429 时「原地等待重试」还是立即 failover。
 	RetryAfter time.Duration
+	// Detail 服务端诊断上下文（如上游请求 URL），仅出现在 Error() 输出即日志中。
+	// 客户端响应只取 Message 字段（见 WriteRelayError），故此字段不会泄露上游地址。
+	Detail string
 }
 
 func (e *RelayError) Error() string {
-	if e.Cause != nil {
-		return e.Message + ": " + e.Cause.Error()
+	msg := e.Message
+	if e.Detail != "" {
+		msg += " [" + e.Detail + "]"
 	}
-	return e.Message
+	if e.Cause != nil {
+		return msg + ": " + e.Cause.Error()
+	}
+	return msg
 }
 
 func (e *RelayError) Unwrap() error {
 	return e.Cause
 }
 
-// NewUpstreamError 创建上游错误
+// NewUpstreamError 创建上游错误。
+// message 为空时（上游返回空响应体）用状态码兜底，避免日志里出现 error=[] 这类无信息量的记录。
 func NewUpstreamError(statusCode int, message string, cause error) *RelayError {
+	if strings.TrimSpace(message) == "" && cause == nil {
+		message = "upstream returned HTTP " + strconv.Itoa(statusCode) + " with empty response body"
+	}
 	return &RelayError{
 		StatusCode: statusCode,
 		Message:    message,
@@ -53,6 +64,17 @@ func NewUpstreamError(statusCode int, message string, cause error) *RelayError {
 	}
 }
 
+// NewUpstreamErrorFromResponse 由上游响应构造错误，并把请求 URL 记入 Detail 供日志定位。
+// 空响应体的 4xx 通常是 URL 路径拼错（被上游网关在路由层拒绝），此时 URL 是唯一有效线索。
+func NewUpstreamErrorFromResponse(resp *http.Response, body []byte) *RelayError {
+	e := NewUpstreamError(resp.StatusCode, string(body), nil).
+		WithRetryAfter(RetryAfterFromHeader(resp.Header))
+	if resp.Request != nil && resp.Request.URL != nil {
+		e.Detail = "upstream_url=" + resp.Request.URL.String()
+	}
+	return e
+}
+
 // WithRetryAfter 附着上游 Retry-After 解析结果（链式调用，d<=0 时不生效）。
 func (e *RelayError) WithRetryAfter(d time.Duration) *RelayError {
 	if e != nil && d > 0 {
diff --git a/web/admin/src/views/ai/ChannelsPage.vue b/web/admin/src/views/ai/ChannelsPage.vue
index fe1c0be..22fa49b 100644
--- a/web/admin/src/views/ai/ChannelsPage.vue
+++ b/web/admin/src/views/ai/ChannelsPage.vue
@@ -194,7 +194,7 @@ const providerDefaultURLs: Record<number, string> = {
   1: 'https://api.openai.com',
   2: 'https://api.anthropic.com',
   3: 'https://generativelanguage.googleapis.com',
-  4: 'https://dashscope.aliyuncs.com/compatible-mode',
+  4: 'https://dashscope.aliyuncs.com',
   6: 'https://hunyuan.tencentcloudapi.com',
   7: 'https://open.bigmodel.cn/api/paas',
   8: 'https://api.deepseek.com',