The issue basically consists of 3 parts. Web settings, sms function, email function. Refer the following check list to troubleshoot in sequence.
1. Check the settings on web to see if anything incorrect:
2. Understand the SMS to Email work flow: SMS to Email Work Flow
1. Get the SMSCore debug log: SMSCore Debug
2. Check the Receiving SMS Failure Troubleshooting
1. Check and test the SMTP settings: Email Settings on Yeastar Products
2. SMTP Settings Troubleshooting: SMTP Settings Troubleshooting
Log & Packet Capture
Post us the logs in above steps if you could not solve the issue.