Some users unable to edit

I have a client, who is set up as an administrator for his wordpress site. I am the developer, and created a slideshow as an administrator, and my client is unable to edit my slideshow (change or add slides). Any changes will not be saved when he tries. I have tried different users with different settings and it all works from my end. Has anyone had issues where some users cannot edit but others can with the same role settings?

Also he can create a slideshow but cannot add slides. It just doesnt save.

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