As it stands unfortunately we don't have enough information to offer you any advice or help.
Please note that in order to get help we need information and your post is devoid of anything useful so also include anything that will help us help you.
Stuff like what device you have?
What app this happens with?
How long it has been happening?
What you're doing to work around the issue or what you've tried and if it worked?
Have you tried another app? A lot of times regardless of MFGR a phone will have two SMS apps, unless that isn't SMS, so try one of your other apps. If you don't have two get one that you trust from the Play Store and try it.