Cannot load plugin settings

Hi everybody.

Like the title says, I’m not able to load any plugin settings. When I click on the settings, I just have a blank page with a grey rectangole and the sentence “Cannot load” and the plugin name, in example “Cannot load enjoyinstagram_plugin_options.”

I have only a couple of plugins working at the moment “Enjoy instagram” (which, not being able to work on settings I can’t use) and “Download Manager”, which seems to work fine, but of which I can’t even see the option of the Settings.

Is this a problem database related?
Before uploading the website online, I had worked on it in local and, in order to upload the database, I had to do a hack explained here, because of the sql error ‘utf8mb4_unicode_ci’.

EDIT: I would like to notice that Download Manager was already installed before uploading, while I’ve installed Enjoy Instagram after the uploading.

Any help, please?
Thanks in advance.