Conflicts and breaks backend

This doesn’t happen with the plugin disabled? What about other plugins disabled and just the Simple Calendar one enabled, does it still affect the menus and widgets then?

Nick, I tried all the environments and scenarios you mentioned here and this is how I found out it was this plugin.

Yes, this does not happen when the plugin is disabled/removed.

The only plugins I have installed on the site is Jetpack and Simple Calendar (aka Google Calendar Events). Tried disabling one at a time (basic troubleshooting technique) and that’s how I came to the conclusion.

Thanks,
JLG

In addition, a 404 error appears when clicking on “clear cache” in the “Calendars” screen. (when the plugin is enabled, that is)

And the widget cannot be added to any location. When attempted, the widget does not appear to retrieve the calendar, and the spinning “loading” icon never stops “loading. It basically sit there and does nothing.

On my site the calendar widget was working ok.
Until I clicked “clear cache”
Now the widget does not load anymore and ‘hangs’ the website.
Had to deactivate the calendar to make the website working again.
So there goes something wrong with the clear cache!

Got update, but having the same issue as peterpc mentioned here.

Ok thanks for the updates. Are you getting any sort of error message for this or does it just sit there loading forever? Maybe a timeout error or something at the end?

No, just loading forever.
And the rest of the page won’t show up.

No error message. Just the spinning ball.

Ok and just to be sure this is happening in the admin area not on the front end of the site, is that correct?

No it is also happening in the frontend of the site.
When I open the site, and I am not logged in, the text stops at the calendar.
Other widgets don’t show.
But if I then go to another page, the calendar is showing the calendar that I did not clear the cache.( I use 3 calendars)
So I have to deactivate the plugin to let the website work.

Can you try turning WP_DEBUG on ( https://codex.www.ads-software.com/WP_DEBUG ) to see if it spits out any sort of error message?

Is this happening because of specific Jetpack module that is enabled?

Do you have a link to a page where I can see the issue?

turned debug on and this is the error on the place the calendar should display:
Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 512817 bytes) in /home/riethove/domains/riethovensetennisvereniging.nl/public_html/rtv/wp-includes/wp-db.php on line 2964

added :
define(‘WP_MEMORY_LIMIT’, ’96M’);
in wpconfig.php file and all is well again!

Great glad to hear that peterpc!

@jedijenn,

Were you able to try the test with WP_DEBUG and get anything?

If I’ve read how to use WP_DEBUG properly(defining parameters in wp-config.php), I should have a log in my wp-content folder, which I do not have, so I am guess there is no error being generated.

However, in my server error log:

https://fanchi.kisekinohana.net/wp-admin/widgets.php
[Mon Dec 21 14:14:20 2015] [error] [client 108.247.251.10] Premature end of script headers: admin-ajax.php, referer: https://fanchi.kisekinohana.net/wp-admin/widgets.php