If email works on one device but not another, the domain is usually not the first thing to change. Check the failing device’s account, authentication, sync and outgoing-mail settings first.
One device working is useful evidence
If your phone can send and receive mail but your computer cannot, the email service itself may still be working. That narrows the investigation. Start with the device that fails rather than changing DNS records or moving the mailbox.
1. Confirm which account is actually configured
Make sure the computer is using the correct business email address and not an old mailbox, alias or personal account. This sounds obvious, but saved credentials and multiple accounts can make a simple problem confusing.
2. Check authentication and recent password changes
Modern business email providers may use OAuth or other authentication flows rather than a simple stored password. If a password was changed, multi-factor authentication was enabled, or an administrator changed a security policy, the computer may need to authenticate again.
3. Check sync and outgoing mail separately
A device may receive messages but fail to send, or send successfully but fail to sync the inbox. Test both directions. For older mail clients, also check whether IMAP/SMTP settings are still supported by the provider.
4. Look for stale or duplicate account settings
Removing and re-adding an account can sometimes fix a damaged local configuration, but do not do this blindly if the mailbox contains locally stored folders or unsynchronised mail. First understand how the client stores the messages.
5. Check the provider before touching DNS
If webmail works and another device works, DNS is unlikely to be the immediate cause of a single-computer problem. DNS becomes more relevant when the whole domain has mail-delivery problems or records have recently changed.
When professional help is worthwhile
If several users have different symptoms, a recent migration happened, or the business uses Microsoft 365, Google Workspace and custom DNS together, map the complete setup first. A clean account and authentication review is safer than repeatedly changing mail records.