The requested TCP address did not respond within the specified threshold.
When the TCP address is checked by our servers, we wait the specified threshold for a response. If our servers do not receive a response before the threshold time, this error is triggered.
Additional Information
TCP addresses can specify a threshold, which allows the request to timeout earlier than the default 15 seconds. With this failure, you might also recieve a TCP Connect failure.
TCP (Transmission Control Protocol) is a specific way to transmit and format data over a network between two IP addresses, hence TCP/IP. Most web traffic uses the TCP protocol, including email and other protocols, such as HTTP, HTTPS, SMTP, POP3, IMAP, SSH,and FTP.
If a TCP hostname is requested (e.g. example.com), the request goes out to a DNS server and gets converted into an IP address.
Troubleshooting
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Double check the TCP address, including the port.
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Double check the threshold that was set.
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If using a hostname, try running a DNS Lookup on your domain to see if there are any issues with your DNS servers.
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If you are a paid member of MxToolbox, you can view the history and performance data of a monitor you’ve set up to pinpoint when this problem started occurring.
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One of the best ways to get help if you are a MxToolbox paid member is to create a support ticket, and one of our staff will be happy to assist you.
Your Email Deliverability is in Jeopardy!
Blacklisting is a sign that you are not actively managing your email deliverability. Other technologies - SPF, DKIM and DMARC are now just as important to get your email placed in the Inbox of your recipients. If you aren’t managing email deliverability, your message may never be heard.
MxToolbox Delivery Center Features:
- Insight into your SPF, DKIM and DMARC configuration to ensure your sending email properly
- DMARC Compliance checks for all of your reported email
- Adaptive Blacklist Monitoring of all your email senders
- Recommendations for improving DMARC compliance and DMARC policies
- Event-based reminders for emergent issues and on-going maintenance
DMARC is a necessity for your business!
Learn More about Email Delivery