Newly bought mobile phones (cottage phones) sometimes can't send text messages, but the other party sometimes receives text messages. Is this a problem with the mobile phone?

Part of it is that because of the poor cell phone signal, the operator can't verify the information you sent, and then the information was sent, but your cell phone didn't receive the verification information, so your cell phone will remind you as a sending failure. Of course, the other party must have received the message. As for the signal difference, it may be your mobile phone or your signal difference!