diff --git a/src/utils/jmap.ts b/src/utils/jmap.ts
index 0bbbb6d..f31da0a 100644
--- a/src/utils/jmap.ts
+++ b/src/utils/jmap.ts
@@ -159,8 +159,16 @@ export class JmapClient {
       to: opts.to.map((t) => ({ name: t.name || '', email: t.email })),
       subject: opts.subject,
     }
-    if (opts.htmlBody) emailData.htmlBody = [{ type: 'text/html', value: opts.htmlBody }]
-    if (opts.textBody) emailData.textBody = [{ type: 'text/plain', value: opts.textBody }]
+    // 正文必须用标准 JMAP bodyValues + partId 引用方式：
+    // Stalwart v0.11 不允许在 textBody/htmlBody 数组里内联 value（报 invalidProperties "Cannot set property."）
+    if (opts.htmlBody) {
+      emailData.htmlBody = [{ partId: '2', type: 'text/html' }]
+      emailData.bodyValues = { '2': { value: opts.htmlBody } }
+    }
+    if (opts.textBody) {
+      emailData.textBody = [{ partId: '1', type: 'text/plain' }]
+      emailData.bodyValues = { ...(emailData.bodyValues as Record<string, unknown>), '1': { value: opts.textBody } }
+    }
 
     const result = await this.request([
       ['Email/set', { accountId: this.accountId, create: { d1: emailData } }, 'c1'],
@@ -186,5 +194,13 @@ export class JmapClient {
       const firstErr = Object.values(err.notCreated || {})[0] as { type?: string; description?: string } | undefined
       throw new Error(firstErr?.description || '创建邮件失败')
     }
+
+    // 检查 EmailSubmission/set 结果（methodResponses[1]）：Email/set 成功不代表已投递
+    const [, submitted] = result.methodResponses[1] || []
+    const submittedData = submitted as unknown as { created?: Record<string, unknown>; notCreated?: Record<string, unknown> }
+    if (!submittedData?.created) {
+      const subErr = Object.values(submittedData?.notCreated || {})[0] as { type?: string; description?: string } | undefined
+      throw new Error(subErr?.description || '邮件发送失败')
+    }
   }
 }