There are few things that causes your message to be delayed:

1. Location Issues
Your device may be located outside the coverage area of your carrier or something is blocking the signal.

2. Mobile Device Issues
Phone may have damages resulting in delayed messages. A weak or uncharged battery may also affect message delivery.

3. Different Networks
A text sender and receiver using different networks may have a greater chance of experiencing texting delays than those using the same network.

4. Network Traffic
There are differing opinions as to whether texting during periods of heavy network use impacts text delivery speed.

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