Unit Elements missing

Hey there geraldine90,

How are you doing today?

No there isn’t any limit on number of units that you can ad per course, could you please try testing for conflicts to see if your theme or any other plugin is causing this?

To do that please try using default WordPress theme like Twenty Fifteen and deactivating all other plugins as displayed in the following flowchart to know which theme/plugin is conflicting if any.

https://premium.wpmudev.org/wp-content/uploads/2013/12/Support-Process-Support-Process.png

Please let me know if you find anything ??

Cheers,
Bojan