Error message for related issue is too far from the area

Problem

• The error message displays under the navigation. It might have few problems:
• It's easy to ignore.
• User doesn't think it an error message related to Related issue.
• If there are two links in the input field, one is invalid and another one is valid, the valid link will be added to Related issues section after clicking Add button. However, the invalid one will disappear without explanation.

Proposal

• The error message displays under the input field.
• The invalid link has red background, so if there are 2 links, user still can know which link is invalid.
• If there are two or more links in the input field and we detect that one of the links is invalid, we should not allow user to add the links. Instead, if user removes the invalid link(s), user can add the valid one to Related issues.