Having issue with verifying emails of custom domain

[eeeeeeeeeee555]

tuyensinh@ued.udn.vn
ajdsghfdjhgr4@ued.udn.vn

I tried to test 2 email address with your library but it is giving same answer although the second one isn't existed. Can you tell me what wrong I did ?

This is result I got:
smtp validation result: &{true false true false false}

[lryong]

@eeeeeeeeeee555 I tested the two email addresses you provided above，the results of the validation are as follows：

{
    "email": "tuyensinh@ued.udn.vn",
    "disposable": false,
    "reachable": "unknown",
    "role_account": false,
    "free": false,
    "syntax": {
        "username": "tuyensinh",
        "domain": "ued.udn.vn",
        "valid": true
    },
    "has_mx_records": true,
    "smtp": {
        "host_exists": true,
        "full_inbox": false,
        "catch_all": true,
        "deliverable": false,
        "disabled": false
    },
    "gravatar": null,
    "suggestion": ""
}
{
    "email": "ajdsghfdjhgr4@ued.udn.vn",
    "disposable": false,
    "reachable": "unknown",
    "role_account": false,
    "free": false,
    "syntax": {
        "username": "ajdsghfdjhgr4",
        "domain": "ued.udn.vn",
        "valid": true
    },
    "has_mx_records": true,
    "smtp": {
        "host_exists": true,
        "full_inbox": false,
        "catch_all": true,
        "deliverable": false,
        "disabled": false
    },
    "gravatar": null,
    "suggestion": ""
}

The reachability of both email addresses is unknown, because there is no way to determine whether the specific email recipient（via smtp.deliverable field） can receive the email.

[eeeeeeeeeee555]

hi,
I tried some verifier services and they can detect if the email address is valid or not
For example:
https://hunter.io/verify/tuyensinh@ued.udn.vn
https://hunter.io/verify/ajdsghfdjhgr4@ued.udn.vn

or you can try here as well: https://breadcrumbs.io/email-verification/#/

How they can detect it ?

[eeeeeeeeeee555]

i think some email providers blocked ip from using smtp. It happens when I verify an email address that use outlook mx record.

[lryong]

@eeeeeeeeeee555 Yes, many SMTP ports being blocked by the ISP，you can find these verifier service providers' technical support and ask them how to implement email verification.（I think they has their unblocked SMTP ports）

[civil-dude]

I opened 25 port on my win 10 machine and tried, It does not work. I don't understand how they can block my ip in first time. I mean I am in not in the list. I think I have to purchase hosting and smtp service then I can verify emails like professional services hunter.io or neverbounce?
Just looking for suggestion....