Next and Previous Month Button

Hi, we’ve been using your plugin for a while with no problems, but now our next and previous buttons seem to have disappeared.

We have not made any changes to our theme or the plugin itself. We’ve been trying to figure out why this happened but nothing we tried so far has worked.

Would you be able to kindly point out some possible causes for this issue and where we could start tracking it down? Your assistance is very much appreciated.

Thank you!

https://ww.wp.xz.cn/plugins/wp-fullcalendar/