Hi Dan,
Thank you for contacting the Microsoft Community.
We appreciate reaching out for assistance on setting up your Microsoft Certification Profile. We are very much aware of the assistance you need as we know that you're trying to get a student discount for certifications and have encountered an issue when attempting to connect your Learn profile to your Certification profile. Allow me to provide you with information to further assist you with.
For us to check if you indeed have a certification profile, we kindly request you to provide us with the necessary information through private message for us to have this check and review.
To identify yourself as a student in your certification profile and verify your academic status once you have indeed a certification account, please be guided by the steps provided below:
Open Problem Steps Recorder (PSR) for Windows | Click this link if MAC device
Make sure you have the latest browser (Edge/Chrome/IE or Mozilla Firefox) and try using your browser in InPrivate/Incognito.
Clear browser cache and cookies and allow all cookies/third party cookies on your browser settings.
On your Learn Profile, click on the photo avatar and select “Settings” from the dropdown menu.
Scroll down to the Connected certification profile section of the page and click “Manage certification profile and exam discounts.”
To edit your profile, select the pencil icon next to “Certification profile” and in the “Job title” dropdown, select “Student”.
Look for the academic pricing notice that appears below the “Job title” dropdown and select “Get verified now”.
Verify your academic status by selecting one of the accepted methods and following the instructions.
To confirm that your academic status verification is successful, make sure the “Job title” field says “Student—verified”.
Additionally, after completing the above steps, please allow 3-5 business days for your documentation to be reviewed, and if the student verification step was successful and your certification profile shows "Student—verified" under the job title on the registration page when scheduling an exam. This will enable you to get 30% off for Fundamental Exams and 45% off for Role-Based Exams (except India and China), and discount will automatically deduct the original price at the checkout page. You may refer to the image below:

If in any case that you are having trouble getting your student status verified, kindly provide us with the necessary information along with the step-by-step screenshot of the process using Problem Steps Recorder (PSR) (click this link for MAC device), starting from the sign-in page up until where the issue occurs through the private message for us to further check this and review.
Moreover, since you mentioned that you have registered for the MS Fundamental test with CertiPort using the student link, the certification profile hasn't appeared on your Microsoft account. It is also important to note that student discounts are only for Pearson VUE.
In addition, your observation about the use of different emails (personal for the certification profile and work/school for the Learn profile) might be the cause of complications in synchronizing the profiles.
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 Message.
Best Regards,