[Bug]: SMTP sending assumes SMTP User as having a domain name

[fbatschi]

Issue Description

In order to authenticate against a custom SMTP server (SMTP_ENABLE=true), the env var SMTP_USER_EMAIL is used.

In my case the user to authenticate does not have a @domain.tld in it, just smtpuser

Problem is, the SMTP_USER_EMAIL is also used as the MAIL FROM in the SMTP connect. This leads to an SMTP error

error in send OTP mail Error: Mail command failed: 501 5.5.4 Invalid FROM: Missing domain
     at SMTPConnection._formatError (/usr/src/app/node_modules/nodemailer/lib/smtp-connection/index.js:807:19)
     at SMTPConnection._actionMAIL (/usr/src/app/node_modules/nodemailer/lib/smtp-connection/index.js:1616:34)
     at SMTPConnection.<anonymous> (/usr/src/app/node_modules/nodemailer/lib/smtp-connection/index.js:1085:18)
     at SMTPConnection._processResponse (/usr/src/app/node_modules/nodemailer/lib/smtp-connection/index.js:991:20)
     at SMTPConnection._onData (/usr/src/app/node_modules/nodemailer/lib/smtp-connection/index.js:772:14)
     at SMTPConnection._onSocketData (/usr/src/app/node_modules/nodemailer/lib/smtp-connection/index.js:195:44)
     at TLSSocket.emit (node:events:519:28)
     at TLSSocket.emit (node:domain:488:12)
     at addChunk (node:internal/streams/readable:559:12)
     at readableAddChunkPushByteMode (node:internal/streams/readable:510:3) {
   code: 'EENVELOPE',
   response: '501 5.5.4 Invalid FROM: Missing domain',
   responseCode: 501,
   command: 'MAIL FROM'
 }

Expected Behavior

There should be an additional, different env var, that defines the sender email address to use. For instance SMTP_FROM where you can set the name and email address to use as sender.

Current Behavior

The smtp user to authenticate with is also used as the mail sender.

Steps to reproduce

No response

Screenshots of the issue(optional)

No response

Operating System [e.g. MacOS Sonoma 14.1, Windows 11]

No response

What browsers are you seeing the problem on?

No response

What version of OpenSign™ are you seeing this issue on? [e.g. 1.0.6]

2.4.1

What environment are you seeing the problem on?

Hosted (app.yourdomain.com)

Please check the boxes that apply to this issue report.

• I have searched the existing issues & discussions to make sure that this is not a duplicate.

Code of Conduct

• I agree to follow this project's Code of Conduct
• I have searched the existing issues & discussions to make sure that this is not a duplicate.