Uncaught TypeError: Cannot read properties of undefined (reading ‘concat’)

Dear @itheta, thanks for reaching out and sorry to hear about your issue,

May I kindly ask you to specify the URL of the page with the faulty gallery?

Our team will check it and try our best to figure out a fix ASAP,

Many thanks!

https://sofiamavridi.gr/gallery/

Dear @itheta,

Thanks for reporting the issue,

Our team located no JS errors linked to our plugin on the page – It appears to be coming from a conflict with your theme or any of the plugins,

You can troubleshoot it with Health Check plugin ,

To troubleshoot, go to Tools > Site Health > Troubleshooting and then select Enable Troubleshooting Mode.

Once in Troubleshooting Mode, you can control which theme and plugins are enabled in the troubleshooting session. Initially, all plugins are disabled and the theme is set to a default one (only on backend – your visitors will not see any alterations on your live site).

Enable just our Photo Gallery plugin and check if the issue is fixed with other plugins/theme disabled,

Then you can re-enable plugins/theme one-by-one to diagnose the culprit,

Please keep us posted on your findings