Fix smtp email sending and connection issues

The connection issue for users using custom SMTPs
 has been resolved.
Improved Email Reliability:
 Eliminates protocol-related transport errors and ensures seamless connection with all supported SMTP providers.
Increased Deliverability:
 More stable email flows for transactional, onboarding, and marketing messages.
Fewer Support Cases:
 Reduces internal triage time caused by email send failures tied to low-level connection errors.