Sign in to your dashboard https://yourdomain.tld/wp-admin
Go to WP Mail SMTP on the left
Enter a valid email address (at yourdomain.tld) into From Email and SMTP Username
Enter a name into From Name
Set SMTP Host to tsr.txtatek.co.nz
Set Encryption to TLS
SMTP Port 587
Authentication ON
SMTP Password should be set in your WP-Config, for testing purposes you can set it in the SMTP Password feild
Save Settings
Go to the Email Test tab and run an email test
Suggestions
Setup a noreply@yourdomain.tld if you do not wish to allow people to reply to your emails, and set it’s quota to something small so it won’t store emails
It is a good idea to use Force From Email (see Option 1)
Common Issues
Your email address is not setup to receive mail (the SMTP server does a lookup to check your mailbox exists and is enabled before it allows you to send mail)