Email Not Sending or Receiving: A Step-by-Step Troubleshooting Checklist

To fix email that will not send or receive, start by logging in to webmail. If webmail works but Outlook or your phone does not, the problem is in your mail app settings: server name, port (993, 465 or 587), SSL, or a username that is not the full email address. If webmail also fails, check the domain's MX and mail A records, the mailbox quota, account suspension and whether your IP has been blocked. This checklist covers cPanel email on Cloudesta shared hosting and ZYROXI Mail business email.

Prerequisites

• The full email address and its current password.
• For cPanel mail, access to your cPanel account. For ZYROXI Mail, the welcome email with your webmail URL and IMAP/SMTP hosts.
• Access to the DNS zone for your domain, wherever your nameservers point.
• Optional: a terminal on Linux, macOS or a VPS, or PowerShell on Windows, for the DNS and port tests.

1. Is the problem my email app or the mailbox itself?

Log in to webmail and send a test message to an outside address, such as a Gmail account. Then reply to it from that outside address.

• cPanel mail: open https://example.com:2096 or https://webmail.example.com. You can also go to cPanel → Email → Email Accounts → Check Email.
• ZYROXI Mail: use the webmail URL from your welcome email.

If both directions work in webmail, go to section 2. If you cannot log in at all, go to section 3. If only sending fails, use section 4. If only receiving fails, use section 5.

2. What settings should Outlook or my phone use?

Most app problems come from four values: the server name, the port, the encryption type and the username.

• Username: the full address, for example info@example.com, never just info.
• Incoming (IMAP): port 993, SSL/TLS. Use POP3 on port 995 only if you really want messages downloaded and removed from the server.
• Outgoing (SMTP): port 465 with SSL/TLS, or port 587 with STARTTLS. Authentication must be turned on, using the same username and password as incoming.

cPanel mail

In cPanel, go to Email → Email Accounts and click Connect Devices next to the account. Copy the values listed under Secure SSL/TLS Settings. The server shown there is often the server's hostname rather than mail.example.com. Using that hostname avoids certificate warnings.

ZYROXI Mail business email

Use the exact IMAP and SMTP hosts and ports printed in your welcome email. Do not use mail.example.com or your cPanel server's settings, because ZYROXI Mail runs on separate servers from your website hosting.

3. Why is nothing working, not even webmail?

Check DNS: MX and the mail host A record

Run these commands on Linux or macOS. On Ubuntu 22.04 or 24.04, install dig first with sudo apt install dnsutils if it is missing.

dig +short MX example.com
dig +short A mail.example.com
dig +short NS example.com

On Windows PowerShell, use:

Resolve-DnsName example.com -Type MX
Resolve-DnsName mail.example.com -Type A

What the results should show:

• cPanel mail: the MX should point to mail.example.com (or your server), and that name should resolve to your hosting IP, for example 203.0.113.10.
• ZYROXI Mail: the MX must match the records in your welcome email exactly.
• Empty or old results: fix the records at whichever provider the NS output shows. In cPanel, that is Domains → Zone Editor. DNS changes can take a few hours to spread.

Check quota and suspension

In cPanel, open Email → Email Accounts.

• If the storage bar is full, click Manage and raise Allocated Storage, or delete old mail.
• If the account shows as restricted or suspended for login, sending or receiving, use Manage to lift the restriction.
• If the whole hosting account or its outgoing mail was suspended by us, often because of unpaid invoices or spam detection, open a ticket.

Check for a blocked IP

Repeated failed logins can get your public IP blocked by the server firewall. This blocks webmail and your apps together. A quick test is to try from mobile data instead of your office Wi-Fi. If that works, open a ticket and include your public IP so we can check and remove the block.

4. Why can I receive email but not send it?

• SMTP authentication: make sure "My outgoing server requires authentication" is enabled in your app.
• Port 25 blocked: many home and mobile ISPs block outbound port 25. Switch your app to 465 (SSL/TLS) or 587 (STARTTLS).
• Bounces from the recipient's server: check whether your domain is missing SPF or DKIM records. In cPanel, open Email → Email Deliverability and click Repair on any record it flags.
• Sending limits on shared hosting: hourly limits apply. Bulk mailings belong on a dedicated newsletter service.

To test whether the SMTP ports are reachable from your network:

nc -vz mail.example.com 587
nc -vz mail.example.com 465
openssl s_client -connect mail.example.com:465 -quiet

A 220 greeting from openssl means the server is reachable. Press Ctrl+C to exit. On Windows, use Test-NetConnection mail.example.com -Port 587 instead.

If you run your own mail server on a Cloud VPS, you will also need reverse DNS (PTR) for your IP. Only the provider can set rDNS, so request it through a support ticket.

5. Why can I send email but not receive it?

• Wrong MX record: re-run dig +short MX example.com. A leftover MX from an old provider sends your mail there instead.
• Local vs remote routing (cPanel): go to Email → Email Routing.
  • If your mailboxes are on cPanel, choose Local Mail Exchanger.
  • If you use ZYROXI Mail or another external service, choose Remote Mail Exchanger. Otherwise, mail sent from your website will be delivered locally and never reach the real mailbox.
• Mailbox full: senders get a 552 bounce. Raise the quota or delete old mail.
• Spam filtering: check your webmail Spam/Junk folder and cPanel → Email → Spam Filters. If "Auto-Delete Spam" is on with a low score, lower its aggressiveness or whitelist the sender.
• Trace a specific message: use cPanel → Email → Track Delivery to see what happened to it.

6. How do I read a bounce (NDR) message?

Codes starting with 5 are permanent failures, and you must fix something before resending. Codes starting with 4 are temporary, and the server will retry automatically.

• 550 5.1.1 User unknown: the recipient address is misspelled or the mailbox does not exist.
• 554 5.7.1 Rejected: the receiving server refused the message on policy grounds. Common causes are a failed SPF/DKIM check, a blacklisted IP or spam-like content. Read the text after the code, which usually names the reason.
• 421 4.7.0 Try again later: this is greylisting or rate limiting. Wait; delivery normally succeeds within 15 to 60 minutes.
• 552 5.2.2 Mailbox full: the recipient's mailbox has no space left.
• 535 5.7.8 Authentication failed: the username or password in your app is wrong.

Verify it works

• Send from your app to an outside address, then reply. Both messages should arrive within a minute or two.
• Check that dig +short MX example.com returns the expected host.
• In cPanel, confirm that Email Deliverability shows no problems for your domain.
• In Gmail, open the received message and use Show original. SPF and DKIM should both say PASS.

Common problems

Frequently asked questions

Should I use port 465 or 587 for SMTP?

Both work. Port 465 uses SSL/TLS from the start, and port 587 uses STARTTLS. Pick whichever your app supports, and keep authentication enabled.

Can I use cPanel email and ZYROXI Mail on the same domain?

Not for the same addresses. The MX record can point to only one mail system, so move fully to business email and set cPanel Email Routing to Remote.

How long do DNS changes for email take?

Usually under an hour, but up to 24 to 48 hours depending on the old record's TTL. Mail sent during that window may still go to the old server.

Need help? Open a ticket at https://cloudesta.com/submitticket.php with the email address, the full bounce message and your public IP, and our team will investigate.