I am having the same issue in our environment. We have a local only SMTP relay setup to allow anonymous requests, but get this same error in nocodb. Did you end up finding a way around this?

No so far I did not solve this. There were other things with priority in the meantime but I am still very keen on getting this running.
Please let me know if you manage!

I spent a few more hours trying then eventually gave up and used Office365 directly with their SMTP service. We would have much preferred to use our relay which is already set up how we like it, but that wasn't in the cards it seems.

I was able to resolve the issue by adding a name parameter with the domain to the nodemailer config. In my case I manually input the domain into the compiled main.js file. Nodemailer stmp documentation states that name is an optional hostname that defaults to hostname of the machine.

Would it be possible to add the name as an input field or set a default value that is derived from the from address?

const config = {
      name: 'your-domain.com', 
      host: this.input?.host,
      ...
}

The idea came from a related discussion on the NodeBB community.

Thanks @MarleTangible for linking this here. Indeed adding the name attribute alone did not help, I additionally had to remove the authentication attribute to allow anonymous authentication.

First modification as suggested:

if (process.env.NC_SMTP_FROM && process.env.NC_SMTP_HOST && process.env.NC_SMTP_PORT) {
    const e = await E.default.getPluginByTitle(y.default.title);
    await E.default.update(e.id, {
        active: !0,
        input: JSON.stringify({
            from: process.env.NC_SMTP_FROM,
            name: 'my-domain.name',
        })
    })

Second modification:

async init() {
    var e, t, a, i, r, l, c, d, u, p, m;
    const _ = {
        ...
        // remove the following lines
        auth: {
            user: null === (u = this.input) || void 0 === u ? void 0 : u.username,
            pass: null === (p = this.input) || void 0 === p ? void 0 : p.password
        },
        ...
    };
    this.transporter = s.default.createTransport(_)
}

To avoid doing this manually all the time I added the following commands to my update script

docker exec -t -i mysql_nocodb_1 sed -i -e "s/from:process.env.NC_SMTP_FROM,host:process.env.NC_SMTP_HOST/from:process.env.NC_SMTP_FROM,name:'my-domain.name',host:process.env.NC_SMTP_HOST/g" docker/main.js
docker exec -t -i mysql_nocodb_1 sed -i -e "s/d.ignoreTLS),auth:{user:null===(u=this.input)||void 0===u?void 0:u.username,pass:null===(m=this.input)||void 0===m?void 0:m.password},tls:/d.ignoreTLS),tls:/g" docker/main.js

From my side, I can live with this solution,. However, I would very much welcome if future versions of NocoDB would include the option for anonymous authentication.

@aretaon Somehow the name parameter on its own worked for me. I had to configure the SMTP as below though which didn't make much sense to me at the time. Maybe the changes you made about removing the authentication solves this issue.

And this is the code I had to replace:
ignoreTLS),auth:{
ignoreTLS),name:'my-domain.com',auth:{

I believe the sed command would look like this:
"s/ignoreTLS),auth:{/ignoreTLS),name:'my-domain.com',auth:{/g"

@MarleTangible Thanks for pointing out the correct position of the name attribute. Nevertheless, I still have to remove the authentication to get it working for me. The SMTP server I use requires implicit TLS over port 465.

@MarleTangible @aretaon Can you try this docker build?

docker run -d -p 8888:8080 nocodb/nocodb-timely:0.205.0-pr-8412-20240506-1153

@DarkPhoenix2704 it worked for me.

Would it be possible to rename the name field to domain or something similar and swap its place with the host? Here's why, despite knowing what the enter, I made the mistake of entering the smtp server details into the name field and I presume this is going to be a very common mistake for any newcomers as well.

From Address: 
From Domain: 
SMTP Server: 
SMTP Port: 
Use Secure Connection: 
Ignore TLS Errors: 
Reject Unauthorized: 
Username: 
Password: 

Updated.

This pr will fix the issue

#8412