Video send but received small thumbnail video iphone14

Hello viet29,

Welcome to Apple Support Communities. Although you do receive the video in this case, we'd recommend using the guidance from If you can't send or receive messages on your iPhone or iPad may help. For instance, making sure your phone number is selected as mentioned in the following section can help to make sure you can receive all message types like MMS and SMS.

"If you have issues with Messages after you set up a new device

If you experience issues like conversations in Messages showing up as separate threads or sent messages appearing as green message bubbles instead of blue message bubbles when you set up a new device, update your settings using the following steps:

1. Update your device to the latest version of iOS or iPadOS if needed.
2. In the Settings app, tap Cellular. Make sure that your phone line is turned on. If you use multiple SIMs, make sure that the phone number you want to use is selected and turned on.
3. In the Settings app, tap Messages. Turn iMessage off and then back on.
4. Tap Send & Receive.
5. Tap the phone number that you want to use with Messages."

All the best.

viet29,

You are very welcome. Glad to have been of help.

Cheers.