Events Booking Invite Friend fails with SMTP Error: data not accepted

Hi Tuan,
 
We are using Joomla 5.4.7 and Events Booking 5.7.x on kendallcameraclub.org.

Joomla Global Configuration → Server → Mail test works successfully using SMTP:
SMTP host: smtppro.zoho.com
Port: 465
Security: SSL/TLS
SMTP user: walter@kendallcameraclub.org

However, the Events Booking “Invite Friend” button fails. The front end shows Joomla’s generic “The requested page can’t be found” error, but with Debug System enabled the call stack shows:

EventbookingControllerEvent->send_invite()
EventbookingModelInvite->sendInvite()
Joomla\CMS\Mail\Mail->sendMail()
PHPMailer\PHPMailer\PHPMailer->smtpSend()
SMTP Error: data not accepted.

The invitation email does not appear in the Events Booking email log, even though “Log Emails” is enabled.

We also checked:
- Events Booking From Email: walter@kendallcameraclub.org
- Reply-To Email: walter@kendallcameraclub.org
- Notification Email: walter@kendallcameraclub.org
- Joomla SMTP test mail sends successfully
- The invitation email subject/body template appears normal

Can you help? 

Could you please submit a support ticket sending us:

- Super user account of your site
- Send us link to the event which I can invite friend and see this error
- Tell me the data which I need to enter in the invite friend form and see that error

I will check to see what's wrong and get it sorted

Regards,

Tuan

Hello

Please go to joomdonation.com/support-tickets.html and submit a support ticket instead of sending information directly on this forum

Regards,

Tuan