MS Outlook makes a connection with the Exchange Server through HTTPS or RPC connection. The connection is configured between the platforms using some secure SSL certificates and if there is problem with these certificates, then the user will have to face different kinds of errors based on type of problem in the certificates.
Error Notifications for Proxy Server Connection Issues
The error messages are always descriptive in nature and they mention the cause of the error itself. Here are some examples:
There is a problem with the proxy server’s security certificate, <Outlook-Profile>. Outlook is unable to connect with this server. (Error-Code).
There is a problem with the proxy server's security certificate. The name on the security certificate is invalid or does not match the name of the target site outlook.office365.com. Outlook is unable to connect to the proxy server (Error-Code).
There is a problem with the proxy server’s security certificate, <Outlook-Profile>. The security certificate is not from a trusted certifying authority. Outlook is unable to connect to this server. (Error-Code).
There is a problem with the proxy server's security certificate, <Outlook-Profile>. The name on the security certificate is invalid or does not match the name of the site. Outlook is unable to connect to this server. (Error-Code)
If you are getting any of the notification mentioned below, know that you are facing this very same error.
Why this error occurs?
Some of the few reasons that cause this error are listed below:
- When you are trying to connect to the server, and it is asking for Certification Authority.
- Non-availability of trusted Certification Authority at the root.
- Invalid certificate.
- Canceled Certificate.
- Due to the intervention from a third-party add-in.
How to fix is “Outlook is Not Able to connect to the proxy server” error?
- Check the Certificate
If you are receiving error notification saying that there is a problem with the security certificate of the proxy server or it is invalid, then you need to check the certificate by following the below-mentioned steps.
- Start with opening the Microsoft Internet Explorer and connect to any secure and trustworthy server.
- Now, press Enter key.
- Now, you will find the padlock icon, double-click on it, and select the Details tab.
- Here comes the most important part, note the information from Valid to and Subject fields. And you are done.
If the date is valid as per the information given in details, and the subject matches the site name, then your certificate gets a green signal. If not, it’s expired, or you need to change the site name.
- Trusted Root Certificate
If you are getting error notification saying that the security certificate is not from a trusted authority, then you need to install a trusted root certificate, let’s see how:
- In the Certificate dialogue box, click on the Install Certificate option. Click on Next to proceed.
- Check the box Place all certificate in the following store.
- Now, click Browse to select the Trusted Root Certification Authorities and click on OK. Click on Next to proceed further.
- Wait for the process, and once it is over click on the Finish button. Click on Ok to put it to an end.
This is how you can install a trusted Root Certificate to overcome with the issue, if still the problem is there, move to the next one.
- Turn Off Third-Party Add-In
If none of the above solutions helped you out, then this one may help you. If the error shows, saying that the security certificate is invalid or does not match the name of the target site, then follow the below-mentioned steps to accomplish the desired results:
- If Outlook is running in your system, close it and press Win+R key to open the Run window.
- In the Run search bar type “outlook.exe /safe” and click on OK.
- If you can operate the safe mode without any issue, that means the problem is with the third-party add-ins.
- To disable third-party add-ins, go to the File option on the top of the Outlook screen.
- Select Options from the file menu and click on Add-ins.
- Locate the manage Box and click on the COM Add-ins.
- Click on Go to move further.
- Do you see the checkbox next to the third-party add-ins? Clear that.
- Restart Outlook.
How to deal with Corruption in Outlook OST?
Well corruption in OST is another common issue user face. OST can get corrupt due to several reasons, and there are not many reliable solutions to fix it with complete integrity. Kernel for OST to PST converter is a good option to deal with any sort of corruption in OST. If you have a corrupt OST and wondering how to fix it, go for the trial version of the software, it is all that you need.
In this blog, we have discussed, what is “Outlook is unable to connect to the proxy server” error and how you can fix it. We have quoted and discussed three manual methods with the help of which you can achieve the desired results. For other Outlook related issues like OST corruption, we have suggested Kernel for OST to PST.