Hey, as @crafter suggested, you should do the following first -
Look for the following lines
$mail = new \PHPMailer\PHPMailer\PHPMailer();
$mail->CharSet = ‘UTF-8’;
$mail->isHTML();
and add a line as indicated
$mail = new \PHPMailer\PHPMailer\PHPMailer();
$mail->CharSet = ‘UTF-8’;
$mail->isHTML();
mail->SMTPDebug = 2;
If you’re not able to locate the file, then contact your system admin first or the hosting support team. They can guide you through it.
As for the ERR_SPDY_PROTOCOL_ERROR, I would like you to check a few sources for the fix.
1.https://www.reddit.com/r/chrome/comments/3ej5ua/err_spdy_protocol_error/