Can't save or edit

Possible causes on WordPress

1

JavaScript error caused a plugin or theme

The most common cause of this problem is when there's a wrong plugin installed, or there's a wrong theme file which causes a JavaScript error on the backend. Use your browser's developers tools to see if that's the case. You might see the error message appearing on refreshing the page, but it could happen, that you will only see it when you try to save on your slide/slider or use the option, which doesn't want to work.

Another option to debug this problem is to run a plugin/theme conflict test and check the problem still happens after each plugin you enabled.

Possible causes on Joomla

1

JavaScript error

This can happen, if you have a wrong extension installed. You should check for JavaScript errors like this to try to figure out what is causing the problem. You might see the error message appearing on refreshing the page, but it could happen, that you will only see it when you try to save on your slide/slider or use the option, which doesn't want to work.

You could try to go to your Extensions → Plugins, filter out the system plugins, and unpublish them (except the Smart Slider 3 System Plugin). If the error goes away after you disabled these plugins, one of them caused the issue. Start turning them back on one by one to see which one is responsible.

Server limitation

1

Server limitation

Try to turn on the Alternative Save Slide option at the Global settings → General. It can help with problems when you can't save because of a server setting, like at some hosts have a setting to prevent saving down URLs.

2

Memory limit

Usually servers are limiting the size of what you are trying to save, so if you managed to save so far, just you made your slider bigger, then this will be your problem and you should contact your server host to increase the memory_limit on your server. Also you could ask them to check the error log, which could also tell the cause.

3

406 - Not Acceptable [...] This error was generated by Mod_Security

Similar error message:

406 - Not Acceptable! An appropriate representation of the requested resource could not be found on this server. This error was generated by Mod_Security.
	

Mod_Security errors mean, that your server host has some security setting, which doesn't allow certain contents to be saved down by your website. This Mod_Security should be turned off at the server, because it is a wrong configuration, as you should be able to save down any content you want to. In most cases there aren't even workarounds for the errors this Mod_Security limitation causes.

So you should contact your server host and ask them to turn off Mod_Security on your server!