Hello,

I have check your generated code, but didn't find a possible issue...

Could you test the module on another site template (for example, protostar) to see if month changes is working ?)
If yes, that means an issue with script conflict with your site template (but don't know why, as seems to have no weird loading of files...)
If with protostar, the calendar is not working, that means a conflict with another extensions (not a joomla core one, but an installed one, such as a plugin or the module slider...)

Regards,
Cyril

jurgenvo wrote: Hi Cyril,

I tried with the protostar template but experienced the same issue. What else can I try to find out what is causing this?

Regards,
Jurgen

Hello,

So, you can check by disabling one by one each plugin and module on that page (third-party plugin) to try to find which plugin/module is making a conflict.

It could take time, but it's easier to know what is the problem, when we know which extension is giving trouble!

Too, make sure all your extensions are updated, as it could be a bug in another extension already solved