Why can't you calculate my foreign tax credit relief?

In previous years, online self-assessment has calculated my foreign tax credit relief for me. This year it says it can't automatically calculate it for me. I don't understand why not? My tax affairs are broadly the same, and there are fewer counties involved than in previous years. Has the policy changed? Am I doing something wrong? I really don't want to do it myself if it can be avoided - help please? Thank you.

Hi Artieleblanc,
The facility for calculating your Foreign Tax Credit relief is still available to calculate in an online tax return.
You will need to contact the self assessment helpline on 0300 200 3310 for help in working this out.
Thank you.