Google script can not send email in my app

Google script can not send email from my app again , it was sending before but I don't know why it can't send again.

Please show your script and relevant blocks. It is best to use GmailApp in your script as contrasted to EmailApp, as EmailApp now has some weird processing that prevents you from sending an email to an address ending with @gmail.com.

This is the script:

function doPost(e) {
  //this function will send email from your gmail address
var recipient = e.parameters.recipient;
    recipient = decodeURI(recipient);
var subject = e.parameters.subject;
    subject = decodeURI(subject);
var body = e.parameters.body;
body = decodeURI(body);

//here is the mail app script to send mails from your gmail address to the user's emails address
MailApp.sendEmail(recipient, subject, body);
}

This is the block.

I tried to download from the app but it's not Clare.

Instead of using EmailApp use GmailApp as mentioned. Also, don't use the decodeURI function in your script - you don't need it. Instead, you will need to encode the parameter details, such as the receiptent email and the body, to URI format using the Web.UriEncode block before you post the text.