i can receive texts but not able to send texts

[DaveGT]

Both my wife and I changed our mobile phones to Apple iPhone 6s. I contacted O2 and requested new sim cards (nano) as we wanted to keep our existing telephone numbers. O2 sent us new sim cards and we put them in the phones. All is good except that we can receive texts but not send texts. We have done all the suggestions made by Apple Support but we still have the same problem. If I look on the iphone at ‘Settings’ then ‘Messages’ with ’iMessages’ ON ‘Send & Receive’ ‘YOU CAN RECEIVE IMESSAGES TO AND REPLY FROM’ it then states my mobile no.  then Verifying…   (with a sun like symbol going round) on the next line is my email address 

It is the same on my wife iphone only with her mobile no.  then verifying… (with a sun like symbol going round), again on the next line is her email address 

Does O2 need to do the verifying? If not has O2 any ideas how we can cure this ‘cannot send texts’ problem.

[MI5]

@DaveGT 

Check the correct number is showing in 

Settings > Phone > My Number.

If not, edit, save and reboot.

[MI5]

@DaveGT 

Can you also edit your phone numbers from your post as the forum is public and you may get spammed.

[DaveGT]

Thank you number edited. the correct number is showing in Settings > Phone > My Number.

[MI5]

@DaveGT 

Verification is done by the phone automatically.

Try resetting yiur network settings if it won't verify and also check the message centre number is correct. 

Guide: Text Message Tips (not sent or received) 

[DaveGT]

Network settings reset - no change. I'm sure I had already tried that. 'Check message centre number is correct' - How do I do that please.

[MI5]

From the Home screen, open the Phone application.
Tap Keypad, then dial the following number: **5005*7672*12063130004#.
Tap the green Call icon. The message Setting Succeeded should display.

[DaveGT]

OK tried that but message came up 'Error performing request Unkown error' I have tried something similar previously to check the SMSC current setting but the same error message as above comes up. I have what should be the correct number to tap in, for pay as you go but when I put that in I get the same error message.

[MI5]

@DaveGT 

OK, a daft question, but have you activated the sim cards by topping up?

[DaveGT]

There was a balance in my account and that went onto the new sim, can't remember when I last topped up but I've just topped up now. No change to the problem yet! Still showing as verifying, would it be instant if it needed activating?