Cannot submit a puzzle: weird message about "Min G-U pairs required"

When submitting a puzzle I get this message. I cannot read well but I suppose is saying I enter a “Min GU” above the total number of pairs… and this is not true.

Can anyone help? Thanks!

[Answered by wawan151 (via chat)]

GU limit is 1/3 total base pairs.

A related issue is that the error message is very difficult to read, as evidenced by the screenshot above