"We can't find your application right now" when attempting to support my application

Re-applying for student finance for what will be my 3rd year in 2024-25; last year my re-application was super simple and took no time at all but when going to get my mother and her husband to support my application last night I got the error:
"We can't find your application right now
Your personal details do not match what the student provided us with in their application. Check if you are using the correct account."
I am 99.9% certain I did absolutely nothing different to last year in terms of entering their details into my application. The only thing I can think that I did wrong is entering their middle names when on their SLC accounts their middle names are not listed - but surely this isn't the issue? When I rang the phone number given under the error, I was told that it could just be a processing delay on the system's end, meaning it isn't able to find my recent application, and to wait 24 hours, but I've just checked again tonight and am getting the same error.
This is made a little more difficult by the fact that my mother and her husband are not particularly technically proficient so when I do my finance applications I also do the supporting part of it myself, with them effectively looking over my shoulder and providing all the details. Needing to get them directly involved and ringing the helpline or doing whatever will almost certainly be a hassle and it is making me anxious.
Is there any way to fix this -- is anyone else getting the same error despite being certain they filled out the form perfectly fine? Or is it just a delay in the system like I was told yesterday?
Thanks

Hi there,
Are you still having this issue?
Thanks,
Claire

Hello,
Yes I just had my mother log in to search for my application again and got the same error.

Hi there,
With the new applications the names do need to match. If a middle name is missing this can cause the system to not locate the application. Your parents can complete the PFF2 form for the time being to ensure we can collect the information we require for your application. The form can be located here https://www.gov.uk/student-finance-forms Thanks, Ross

Hello,
Thanks for this, I'll have them fill out the form today.
Do I just send it in the post with the address provided on the front? Or do I need to provide any additional detail in the form/on the envelope to help connect the form to my account?
Thanks