I haven't tried running it, and I only read the code, but as far as I can tell, the message donorportal-login-problems appears to be used in two different contexts:

1. As the title of the help text "Problems logging in?"
2. As an email subject to complain about problems

All the usages are in the same file, https://gerrit.wikimedia.org/g/mediawiki/extensions/DonationInterface/+/8dcf22402ca5ef7410d5b29b26b8d29d6d9f7ebb/modules/ext.donationInterface.donorPortal/views/LoginView.vue#128

The first usage is probably appropriate, but in the second one, the question mark is probably wrong.

For the email subject, there should probably be a different message.