Symptoms

After modifying MAIL_SERVER_HOST, MAIL_SERVER_PORT, MAIL_SERVER_USERNAME, MAIL_SERVER_PASSWORD, EMAIL_SENDER, and MAIL_SERVER_REQUIRE_TLS  fields, we restarted both TimelinePi and Redis-server. We tried adding users via the Users page under the Account Settings, but we are not receiving any emails.

Timeline logs show message: "Error: 2504:error:1408F10B:SSL routines:ssl3_get_record:wrong version number:c:\ws\deps\openssl\openssl\ssl\record\ssl3_record.c:332"

Cause

The server and the client does not have the same TLS settings. The way Timeline tries to access the mail server is controlled by three environment variables:

MAIL_SERVER_SECURE,

MAIL_SERVER_REQUIRE_TLS,

MAIL_SERVER_REJECT_UNAUTHORIZED.

A typical situation with Exchange servers is that you cannot start the connection under TLS, but you can create a normal TCP connection first, and then upgrade it to an encrypted channel via the STARTTLS command.

Resolution

For this work to with Timeline, please set the following settings:
 
MAIL_SERVER_SECURE=false
MAIL_SERVER_REQUIRE_TLS=true