error 21 . unable to send texts

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  • Updated 1 year ago
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unable to send text messages to someone and im getting error code: 21. Ive been texting this person for quite a while and this is the 1st time that this has happend. I am still able to recieve texts from the person. I can send messages to others. i just tried resetting my phone and that didnt work...
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seansymons89

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Posted 6 years ago

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samsvoc

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Are you using mobile data or wifi to text? Try one and the other to pin point the cause.
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seansymons89

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how do i switch them?
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Ray Luong

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I also have the same problem except that I'm using mobile data to text. Everytime I try to send the text, it gets rejected right away and displays Error Code: 21
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samsvoc

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Best to call Koodo tech support.
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rikkster, Mobile Master

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GSM-CMS Error 21:Short message transfer rejected

Delete and re-enter the persons number you were text messaging to, reboot device (pull battery and SIM card if applicable) to see if that solves the problem. It would be helpful if you could tell us what phone you have. If that fails, call Koodo technical support.
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Python Outcast

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Mine is a kestral and i got my friends number but i know his phone is on but it bleebs 4 times when i try to ring him and whenever i try to text him it does this i really dont know i cant be my phone because i can ring and text everyone else but him my phone is old though and has glitched out before but is it worth going to ee or not but i dont know if he has service at his house so it could be that but then again i have no idea help would be much apreciated thanks
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seansymons89

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its an LG optimus one. and re-entering the number did not work
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Paul Deschamps, Mobile Master

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Did you try pulling out the battery & SIM Card while the phone is on, like Rikkster said?
Have you tried sending a text to someone else?
If you have & it works then it could very well be on the end of the person your texting that failed.
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seansymons89

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i can text others. i just want to find out what error 21 means
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hollywolly

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I also have this problem and its so frustrating. Ii fi d that long texts,causes it. Today I want to forward a text I received to someone and error 21 .my phone is vodaphone smart 6/ IRS brilliant in every wY apart from this. Shall I try taking sim card out. I don't want to lose anything like photos. Thanks if you can help
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Allan, Mobile Master

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If the text is long enough it will be converted to mms which requires data to send.
Either turn on your data or try sending thr message in pieces to fix the problem if this is the case.
(Edited)
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Paul Deschamps, Mobile Master

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Here's all the codes and meanings ;-)

http://www.ozekisms.com/index.php?owp...
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seansymons89

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"Short message transfer rejected" This cause indicates that the equipment sending this cause does not wish to accept this short message, although it could have accepted the short message since the equipment sending this cause is neither busy nor incompatible.

._. so what do i do lol.
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Chad Burr, Mobile Master

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Try deleting your sent text messages. Also look to be sure youre not splitting text messages that option is available in the default messaging app. Im not sure what yall meanby using mobike data to text since sms doesn't require a data connection. Ask tech support to clear your swith when you call in. (mms does require a data connection).
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Paul Deschamps, Mobile Master

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I was wondering the same thing about text & data use, made no sense to me.

Anyways try deleting the contact & clear the call logs & make sure the persons # is nowhere on the device anywhere.
Then while the device is on pull out the battery & SIM Card for a couple minutes, then replace them both after that couple of minutes.
Turn the device back on and then make a new contact of that person making sure to put the full number 1-xxx-xxx-xxxx for them.

If that still doesn't work then have the other person pull their battery & SIM Card out for a couple minutes when the phone is on.
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rikkster, Mobile Master

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CMS ERROR: 21: means that the mobile operator is actively rejecting/blocking this message.

You may have reached the storage limit of both your text and mms messages. You can increase the storage size manually by tapping on the menu button while you're in the text messaging application. By default, the text message limit is 200 messages per conversation and 20 mms messages per conversation. Deleting older conversations could resolve this problem and having the tech rep clear the switch works as well.
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Shawn Wood

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My suggestion would be to delete the contact, and try to send a message by manually entering the number.

Also, is this a Picture message? or just a regular text?
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rikkster, Mobile Master

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That's already been suggested a few times already, seems that method isn't working.
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MykeC

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Hey seansymons89, have you tried clearing your inbox and outbox then tried sedning a text message?
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Muhammad Rameez

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hi..did anyone find the reason we get error 21?
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Chad Burr, Mobile Master

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The reason has been stated twice in this article, your device is rejecting it.

I would suggest trying to send the message with a third party sms app instead of the baked in one. Try GoSMS Pro. See if that works for you. If it does, use that instead for sms for now on.
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Muhammad Rameez

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Thanks for the reply.
I don't have this problem with my phone. I am just trying to find out the reason why mobile phones give this error. As far as my understanding, this error is caused by user's device and not because of some inefficiency of the network. I read on a forum that incorrect format of SMSC number causes this error. Also, in this very thread, it has been mentioned that the error may be caused if SMS/MMS capacity of the sender is exhausted.

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