Menu doesn't display in landscape mode on 6th Generation iPad Air 2

software version 12.4.1 I just received news that welcome.smls.org does not have a menu that drops down when using landscape mode on 6th Generation iPad Air 2. (It is a classroom of children with these iPads and none of them work.) I have tried it with an android tablet, an iPad mini (first generation), and a Galaxy S9 with no issues. Any ideas? Thank you