Hi Muhammad,
Thank you for contacting the Microsoft Community.
We recognize the importance of obtaining support to ensure a successful exam registration, particularly in light of the challenges you have experienced, allow me to take immediate action to assist you.
Please be advised that we have received multiple reports from other candidates encountering the following error message: "We encountered an unexpected error. Please try again later. If this issue continues, please contact site support."
This issue has been raised with our support team and immediately received an update that there is indeed an intermittent issue with exam registration.
For immediate assistance, since you've already attempted multiple browsers and cleared your cache and history. You may also contact the Pearson VUE's Support Team, as they have direct access to exam scheduling or rescheduling. You can contact them via chat or via phone call, just ensure that you select the region that aligns with your location to be redirected to the right support group.
On the other hand, if you are an active ESI learner (wherein your company is part of the ESI program) please note that you need to first contact the ESI Support Team as they are the experts in handling concerns raised by the ESI learners. They are also the ones who can collaborate with Pearson VUE's Support Team on your behalf.
To help you proceed, below are the steps to create a case with the ESI support team:
1. Kindly go to the link provided on private message and login using your company email,
2. Select the Create Case option and provide the information requested on the "Open a New Case"
3. Form and attach all necessary documents such as screenshots of the confirmation email then click submit.
4. You will be provided with a Case ID to track the progress of your case.
You may refer to the image provided below:

If further assistance is needed from our end, you may share the ESI / Pearson VUE Case ID through private message along with the requested information for us to follow up with them on your behalf.
Meanwhile, if you are not an ESI Learner and the issue persists, please provide the requested information in the private message, along with the screen recording that captures the entire process leading up to the error, including the web address bar or URL bar.
Alternatively, you may use Problem Steps Recorder (PSR) if available on your Windows version. Be sure to adjust the settings to capture 100–200 screenshots.
As our goal is to ensure that we will be able to assist you properly, please let us know if additional information is needed.
I look forward to your response. Please note that if no response is received after two business days, the case will be closed and locked. After the case is locked, we will no longer be able to respond, even through Private Messages. Thank you.
Sincerely,