We could not configure smtp for sending emails

Hi,
We configured SMTP parameters like in Attachment.
smtp server : smtp.gmail.com
smtp port : 25
smtp login name : This email address is being protected from spambots. You need JavaScript enabled to view it.
smtp login password : •••••••••••
end of line format for mail : default format (\r\n)
default format (\r\n)
sendmail path :
Mailer Type : Library PHPMailer (recommended)

Function PHPMail

But we have error when sending emails.
The error in the log file is : Extension missing: openssl
2017-05-12 09:31:11.946 ***** ERROR ***** [V6.2.4] Error sending mail
2017-05-12 09:31:11.948 ***** ERROR ***** [V6.2.4] SMTP Server : smtp.gmail.com
2017-05-12 09:31:11.951 ***** ERROR ***** [V6.2.4] SMTP Port : 25
2017-05-12 09:31:11.954 ***** ERROR ***** [V6.2.4] Mail stored in Database : #10
2017-05-12 09:31:11.956 ***** ERROR ***** [V6.2.4] PHPMail error : Extension missing: openssl
2017-05-12 09:31:11.959 ***** ERROR ***** [V6.2.4] PHPMail debug :

Is there any thing to do to solve this problem?

Thanks