diff --git a/src/app/api/whatsapp/broadcast/route.ts b/src/app/api/whatsapp/broadcast/route.ts
index 3091d12..6171d25 100644
--- a/src/app/api/whatsapp/broadcast/route.ts
+++ b/src/app/api/whatsapp/broadcast/route.ts
@@ -2,7 +2,12 @@ import { NextResponse } from 'next/server'
 import { createClient } from '@/lib/supabase/server'
 import { sendTemplateMessage } from '@/lib/whatsapp/meta-api'
 import { decrypt } from '@/lib/whatsapp/encryption'
-import { sanitizePhoneForMeta, isValidE164 } from '@/lib/whatsapp/phone-utils'
+import {
+  sanitizePhoneForMeta,
+  isValidE164,
+  phoneVariants,
+  isRecipientNotAllowedError,
+} from '@/lib/whatsapp/phone-utils'
 
 interface BroadcastResult {
   phone: string
@@ -77,30 +82,55 @@ export async function POST(request: Request) {
         continue
       }
 
-      try {
-        const result = await sendTemplateMessage(
-          accessToken,
-          config.phone_number_id,
-          sanitized,
-          template_name,
-          template_params || [],
-          template_language || 'en_US'
-        )
+      // Correct sendTemplateMessage signature is:
+      //   (phoneNumberId, accessToken, to, templateName, language?, params?)
+      // Previously the args were passed in the wrong order (accessToken first,
+      // params before language), which made Meta reject every broadcast.
+      //
+      // Retry with phone variants on "not in allowed list" so numbers that
+      // differ only in a trunk-prefix 0 still reach recipients.
+      const variants = phoneVariants(sanitized)
+      let sentMessageId: string | null = null
+      let lastError: string | null = null
 
+      for (const variant of variants) {
+        try {
+          const result = await sendTemplateMessage(
+            config.phone_number_id,
+            accessToken,
+            variant,
+            template_name,
+            template_language || 'en_US',
+            template_params || []
+          )
+          sentMessageId = result.messageId
+          lastError = null
+          break
+        } catch (error) {
+          const errorMessage =
+            error instanceof Error ? error.message : 'Unknown error'
+          if (!isRecipientNotAllowedError(errorMessage)) {
+            lastError = errorMessage
+            break // unrelated error — stop retrying
+          }
+          lastError = errorMessage
+          // retry with next variant
+        }
+      }
+
+      if (sentMessageId) {
         results.push({
           phone,
           status: 'sent',
-          whatsapp_message_id: result.messageId,
+          whatsapp_message_id: sentMessageId,
         })
         sentCount++
-      } catch (error) {
-        const errorMessage =
-          error instanceof Error ? error.message : 'Unknown error'
-        console.error(`Failed to send broadcast to ${phone}:`, error)
+      } else {
+        console.error(`Failed to send broadcast to ${phone}:`, lastError)
         results.push({
           phone,
           status: 'failed',
-          error: errorMessage,
+          error: lastError || 'Unknown error',
         })
         failedCount++
       }
diff --git a/src/app/api/whatsapp/send/route.ts b/src/app/api/whatsapp/send/route.ts
index b4cc04c..f8614fd 100644
--- a/src/app/api/whatsapp/send/route.ts
+++ b/src/app/api/whatsapp/send/route.ts
@@ -2,7 +2,12 @@ import { NextResponse } from 'next/server'
 import { createClient } from '@/lib/supabase/server'
 import { sendTextMessage, sendTemplateMessage } from '@/lib/whatsapp/meta-api'
 import { decrypt } from '@/lib/whatsapp/encryption'
-import { sanitizePhoneForMeta, isValidE164 } from '@/lib/whatsapp/phone-utils'
+import {
+  sanitizePhoneForMeta,
+  isValidE164,
+  phoneVariants,
+  isRecipientNotAllowedError,
+} from '@/lib/whatsapp/phone-utils'
 
 export async function POST(request: Request) {
   try {
@@ -99,43 +104,81 @@ export async function POST(request: Request) {
 
     const accessToken = decrypt(config.access_token)
 
-    // Send via Meta API
-    // Function signatures are:
-    //   sendTextMessage(phoneNumberId, accessToken, to, text)
-    //   sendTemplateMessage(phoneNumberId, accessToken, to, templateName, language?, params?)
-    // The args were previously swapped (accessToken before phoneNumberId),
-    // causing Meta to reject every send.
-    let waMessageId: string
+    // Send via Meta API — retry with phone-number variants if Meta rejects
+    // with "recipient not in allowed list" (common in sandbox / when a
+    // number was registered with/without a trunk 0). If an alternate
+    // format succeeds, we persist it back to the contact row so the
+    // next send goes through on the first attempt.
+    let waMessageId = ''
+    let workingPhone = sanitizedPhone
 
-    try {
+    const attempt = async (phone: string): Promise<string> => {
       if (message_type === 'template') {
         const result = await sendTemplateMessage(
           config.phone_number_id,
           accessToken,
-          sanitizedPhone,
+          phone,
           template_name,
-          undefined, // use default language (en_US)
+          undefined, // default language (en_US)
           template_params || []
         )
-        waMessageId = result.messageId
-      } else {
-        const result = await sendTextMessage(
-          config.phone_number_id,
-          accessToken,
-          sanitizedPhone,
-          content_text
-        )
-        waMessageId = result.messageId
+        return result.messageId
       }
+      const result = await sendTextMessage(
+        config.phone_number_id,
+        accessToken,
+        phone,
+        content_text
+      )
+      return result.messageId
+    }
+
+    try {
+      const variants = phoneVariants(sanitizedPhone)
+      let lastError: unknown = null
+
+      for (const variant of variants) {
+        try {
+          waMessageId = await attempt(variant)
+          workingPhone = variant
+          lastError = null
+          break
+        } catch (err) {
+          const message = err instanceof Error ? err.message : String(err)
+          // Only retry when the failure is specifically that the
+          // recipient isn't in Meta's allowed list. Any other error
+          // (bad token, invalid template, etc.) bubbles up immediately.
+          if (!isRecipientNotAllowedError(message)) {
+            throw err
+          }
+          lastError = err
+          console.warn(`[whatsapp/send] variant "${variant}" rejected by Meta, trying next…`)
+        }
+      }
+
+      if (lastError) throw lastError
     } catch (err) {
       const message = err instanceof Error ? err.message : 'Unknown Meta API error'
-      console.error('Meta API send failed:', message)
+      console.error('Meta API send failed for all variants:', message)
       return NextResponse.json(
         { error: `Meta API error: ${message}` },
         { status: 502 }
       )
     }
 
+    // If a non-original variant succeeded, update the contact so future
+    // sends go straight through. sanitizePhoneForMeta on workingPhone
+    // will yield workingPhone itself, so re-storing preserves it.
+    if (workingPhone !== sanitizedPhone) {
+      console.log(
+        `[whatsapp/send] Auto-corrected contact phone: ${sanitizedPhone} → ${workingPhone}`
+      )
+      await supabase
+        .from('contacts')
+        .update({ phone: workingPhone })
+        .eq('id', contact.id)
+    }
+
     // Insert message into DB — field names MUST match the messages schema
     // (see supabase/migrations/001_initial_schema.sql):
     //   conversation_id, sender_type, content_type, content_text,
diff --git a/src/lib/whatsapp/phone-utils.ts b/src/lib/whatsapp/phone-utils.ts
index 74a1f57..2e5da24 100644
--- a/src/lib/whatsapp/phone-utils.ts
+++ b/src/lib/whatsapp/phone-utils.ts
@@ -39,3 +39,66 @@ export function phonesMatch(phone1: string, phone2: string): boolean {
 export function isValidE164(phone: string): boolean {
   return /^\+?[1-9]\d{6,14}$/.test(phone)
 }
+
+/**
+ * Generate plausible phone number variants for retry when Meta's
+ * sandbox rejects a number with error #131030 ("not in allowed list").
+ *
+ * Many countries use a "trunk prefix" 0 for domestic dialing that is
+ * meant to be dropped in international format (e.g. Lithuanian
+ * "+370 063 949 836" domestically → "+370 63 949 836" international).
+ * But some sandboxes register the number with the trunk 0 included,
+ * causing sends to the correct international format to fail.
+ *
+ * This helper yields up to 3 variants:
+ *   1. The original sanitized number (first attempt)
+ *   2. With a trunk 0 inserted after the country code
+ *   3. With a trunk 0 removed after the country code
+ *
+ * Country-code lengths of 1, 2, and 3 digits are tried because we
+ * don't know the user's country ahead of time.
+ *
+ * @param sanitized - digits-only phone number (from sanitizePhoneForMeta)
+ * @returns deduplicated list of variants, original first
+ */
+export function phoneVariants(sanitized: string): string[] {
+  if (!sanitized) return []
+  const seen = new Set<string>()
+  const push = (v: string) => {
+    if (v && !seen.has(v)) seen.add(v)
+  }
+
+  // 1. Original
+  push(sanitized)
+
+  // 2. Insert a 0 after each plausible country-code length
+  for (const ccLen of [1, 2, 3]) {
+    if (sanitized.length <= ccLen) continue
+    const cc = sanitized.slice(0, ccLen)
+    const rest = sanitized.slice(ccLen)
+    if (!rest.startsWith('0')) {
+      push(cc + '0' + rest)
+    }
+  }
+
+  // 3. Remove a leading 0 after each plausible country-code length
+  for (const ccLen of [1, 2, 3]) {
+    if (sanitized.length <= ccLen + 1) continue
+    const cc = sanitized.slice(0, ccLen)
+    const rest = sanitized.slice(ccLen)
+    if (rest.startsWith('0')) {
+      push(cc + rest.slice(1))
+    }
+  }
+
+  return [...seen]
+}
+
+/**
+ * Returns true when the Meta API error indicates the recipient
+ * phone number isn't in the allowed list (sandbox restriction).
+ * Detected via error code 131030 or the standard error text.
+ */
+export function isRecipientNotAllowedError(message: string): boolean {
+  return /131030|not in allowed list|not in the allowed list/i.test(message)
+}