Hi,
Please make sure you are using the most updated version of Photo Gallery plugin (if you are using that), WordPress & your theme. Sometimes it isn’t obvious that there is an update available. Go to Dashboard > Updates and click the Check Again button to be sure.
Furthermore, deactivate all of your plugins except Photo Gallery. If this solves the problem, reactivate each plugin one by one, until you spot the problematic plugin. If found, contact that plugin’s developers for help, or use a different plugin.
Switch your theme (temporarily) to a default WP theme such as Twenty Fifteen to see if your theme is causing an issue. If so, contact the theme’s developers for help, or use a different theme.
Then, clear all cache (server cache, caching plugin, and browser cache).
Thank you!
Have a nice day!
The issue is solved there was a plugin conflict.
Thanks for a quick response.