Outlook send/receive error can occur for a variety of reasons, such as incorrect account settings, network issues, or problems with the mail server. To troubleshoot send/receive errors, start by checking your account settings. Make sure that your account information is correct and that the server settings are correct. If the settings are correct, then try disabling any antivirus or firewall programs, as they can sometimes interfere with sending and receiving emails. If the issue persists, you may need to contact your email provider for further assistance.