Mail not send from the magento2.3.1

Question

I am using Magento 2.3.1 I have installed the Mageplaza Smpt module with its latest core module. When I'm testing a test mail button, this error occurs. I am using yahoo mail to send an mail.

A technical problem with the server created an error. Try again to continue what you were doing. If the problem persists, try again later.

Answer 1

in magento: 2.3, php: 7.2 I got same error: Deprecated Functionality: idn_to_ascii(): INTL_IDNA_VARIANT_2003 is deprecated ..

so I downgrade php version to 7.1 then its work. http://php.net/manual/en/migration72.deprecated.php

or another solution is to upgrade icu to ICU 4.6 http://www.linuxfromscratch.org/blfs/view/8.3/general/icu.html

to check icu current vesion uconv -V

more refer link