Notarizing Electron apps throws - "You must first sign the relevant contracts online. (1048)" error

TLDR: check your developer.apple.com account has admin permissions for your organization and go to https://appstoreconnect.apple.com/ to accept the legal docs.

I also got the error "Error: You must first sign the relevant contracts online. (1048)".

Navigating to developer.apple.com memberships or anything else didn’t reveal prompt. It turned out, my Apple developer account had no "admin" rights within our organization and I could not see the legal prompts, but there was no indication of this.

After a team member with admin access navigated to https://appstoreconnect.apple.com/ there was a pending agreement that had to be accepted and the error went away.

UPD. Comments suggested that the agreements could also be directly reviewed at https://appstoreconnect.apple.com/agreements/#

You can also navigate to https://developer.apple.com/account/#/overview/{companyid}

At the top will be a prompt to agree the updated license agreement. In case you don't have the rights there will be a button which generates an email containing the link to those who can.