I have created a gallery and when I choose a Gallery Type other than vertical, images show for a few milliseconds then disappear. If I use the vertical layout format, it works fine. I use MAgee OneTone theme
Besides, we tried to reproduce your problems on our testing servers and didn’t have any luck. So most likely there is a conflict with your other plugin or your theme. We hope you understand that we can’t test our products with all other plugins and themes that are available on the market, and we can’t control the other developers. Therefore bad code of other plugins or templates can provoke a lot of problems.
Please try to deactivate all your plugins one by one and check the issue. Thus you will find out which plugin causes the error. If it won’t help, try to switch temporarily to a standard WordPress theme. Afterwards let us know about the result. This will help our developers to solve your problem faster.