Error when self-hosting on Vercel

[AustenLamacraft]

I've successfully set up giscus locally but run into the following error when deployed to Vercel the app 403s from GitHub with:
"error:0909006C:PEM routines:get_name:no start line"
This seems to suggest a problem with the private key but I'm using the same format that works locally (even setting the variable with the Vercel CLI)
"-----BEGIN RSA PRIVATE KEY-----\nXXXXXXXXXXXXXXXXXXXXXXXXX\n-----END RSA PRIVATE KEY-----"
Any idea what's going on? I realise it's my problem but I expect I'm missing something simple...

[laymonage]

Have you made sure there's no newlines in the private key?

[exitcas]

The newlines have to be replaced with something?

[laymonage]

No, just remove them.

[AustenLamacraft]

Actually I pasted the version with newlines from the GitHub private key .pem file and it worked! It's a bit of mystery to me...