Have you heard about shared server owners? They often get the compilation of debugging as well as email fixing errors many times.

With the help of protocol called TLS, a sender sends the mail to the recipient but an error called 403 4.7.0 TLS handshake failed occurs in middle. We have described the error format for your reference:

----- The following addresses had permanent fatal errors -----
(reason: 403 4.7.0 TLS handshake failed.)
The so-called error “403 4.7.0 TLS handshake failed” has a fine strategy to interrupt the communication between the mail server and the recipient. Usually, for encrypting the communication TLS protocol is used to transmit the data securely. Yes, it encrypts the data while the email goes to the recipient inbox.

TLS has a substitute to use a protocol namely handshake which ensures the activity of the server. For secure transmission of email, it is advisable to use private and public keys in between the mail server of recipient and sender.

You can ask how it authenticates. It goes for a check-in cipher suites for finding matches able content so that the keys can be shared in-between sender and recipient servers. Most probably, this error occurs when handshake protocol fails to send an encrypted message then you will get an error 403 4.7.0 TLS.

Let us see how to fix this problem by identifying the error appearance in any of the below five strategies.
  • Errors in SSL Certificate:
A server must have an SSL certificate to send a transmission of TLS securely. You should get a certificate from Certificate authority or self-signed team.

The certificates are set up with the limitations of the period. So, do check the SSL certificate has a validity time. If not extend it immediately! Most of the servers, won’t prefer SSL certificate with self-signed authority because it considers that the certificate is failed to have enough trust in processing. Please execute the below statement to find the mail log errors:

TLS client disconnected cleanly (rejected our certificate?)
  • Get to know more about cipher issues:
We all need to be the up-to-date trend right? Then why were we using old versions of SSL certificate and ciphers that are analyzed as a weak one? You must get the latest version of SSL certificate for sending emails in a secure mode. Few of the protocols such as SSLv3 and SSLv4 are filled with vulnerabilities. So, avoid using those protocols for your safety also doesn’t forget to avoid using RC4 which is termed as the weak ciphers among all.
  • Errors in SSL connectivity:
Some problems in network connectivity or firewall may lead to errors in SSL connectivity. For getting a secure connection, just initiate the command “STARTTLS” for email transmission. Use the command:

openssl s_client -starttls smtp -connect host:port
To ensure TLS handshake is working properly or not. Execute the above-shown command to know the problem is in SSL connection or not.
  • Failed to resolve MX record:
There should be connectivity between the sender as well as the recipient mail server. If you have a good MX record, then it is easy to show up a new connection.

dig domain.com MX – This command helps you to identify whether the mail server has properly maintained to resolve or not.

If it works well then you will be getting the result in the Answer section. If not then it fails to resolve MX records.
  • Email client issues:
Whenever you configure TLS, you will be getting an error message from Eudora, InterChange, CommuniGate Pro. In that case, of course, TLS handshake won’t process as you expected. It is not possible to configure other clients for mail like Outlook Express, Thunderbird and Outlook.

We have listed top reasons for fixing 403 4.7.0 TLS handshake failed error. Just go through all for your satisfaction of course you will be get clicked with any of the solutions. You have more enough technical skills to deal with all type of email errors. No more courses no more time consumption. It’s all in your hand to do big surprises all around you!
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