Some problem sending messages

[Yermomlikewhoa]

Hi!
Recently some of my contacts made me notice that they often received some old messages from me each time I restart my phone.
Some messages I thought they received ( because of the delivery report) that I sent them days ago and they actually never received.
It's really annoying
I've already restored the factory settings on my phone but the problem is still there.
Anybody got an idea ?
Thanks

[Uliwooly]

@Yermomlikewhoa

Which messaging app are you using? have you contacted your carrier/network regarding this?

[Yermomlikewhoa]

Thanks for.answering
I'm using the classic messages app I guess I never modified this.
I'm French I've talk to my network about this and they just wanted to.sent my phone to repair shop not explaining to me anything so I said no

[Uliwooly]

@Yermomlikewhoa

Are those messages longer than 160 characters? perhaps they were MMS instead and your data was off? 

[Jake-SonyXperia]

Hi Yermomlikewhoa,

Welcome to the community,

You could try replacing the SIM card, this is more likely to the culprit above software.

[Yermomlikewhoa]

Some of the messages were just two or three words
I'm gonna try to change my sim card
Thanks again for.answering and trying to find a solution for.me

[gordsk]

Verify that you did not inadvertently activate Airplane mode. It will stop texts from the default messaging app that comes with the cellphone. Airplane mode when active (on my Xperia M4 Aqua) was still able to send and receive email, use Facebook and Facebook Messenger apps, and Internet. Airplane mode when active also caused a Network Connection Error from my AccuWeather app that disappeared once I disabled Airplane mode.