This is a real case study from a customer who has consistently used NeoKOSIM’s Vietnam eSIM for multiple trips to Vietnam.

After arriving in Vietnam, the customer tried to send a text message to a friend but encountered a sending failure. Voice calls and data worked perfectly, and messaging through iMessage was also functioning normally. However, only regular SMS messages couldn’t be sent.

Step-by-Step Solution
If you’re experiencing this issue, please follow these steps in order:

Step 1: Check iOS Version
Please verify that your iOS is up to date.
– Example: iOS 18.5 or latest version
– Check via Settings > General > Software Update

Step 2: Verify Message Settings
Check your iPhone’s message-related settings.
* Go to Settings > Messages
* Ensure the following options are enabled (ON):
– iMessage
– Send as SMS
– MMS Messaging

Step 3: Reset Network Settings (Key Solution)
This is the most effective solution.
* Settings > General > Transfer or Reset iPhone > Reset Network Settings
* This procedure resolves most issues.

Additional Tips
* After resetting network settings, you’ll need to re-enter Wi-Fi passwords
* If the problem persists, contact us for additional support
* It’s recommended to test your eSIM settings before traveling
We hope this method helps you resolve SMS sending issues during your Vietnam trip. Have a safe and enjoyable journey to Vietnam!