Google webmaster tools has been reporting numerous (100+) soft 404 page not found errors and all of the pages are coming from Spider Calendar.

This started in late December 2015

Dear Jeff,

Could you please give the 404 Page Not Found links, so we can have a better understanding of the problem? Also, you mentioned it has started in December. Did you update the plugin around that time?

Thank you!

Here is one of several. The date is far in the future. Some show 2014 and 2015.

I added a new calendar and disabled the old calendar, but Google continues to find pages that do not exist.

I have not programmed any events past January of this year.

omahacareernetworking.org/wp-admin/admin-ajax.php?action=spiderbigcalendar_week&theme_id=13&calendar=1&select=month,list,&months=09,10,11&date=2017-10-26&many_sp_calendar=1&cur_page_url=http://omahacareernetworking.org/calendar-2/&cat_id&widget=0&rand=1

As far as updates to the plugin I am not sure when the last update was released and whether the WordPress update last month would have impacted this plugin. I did not have an activity log tool added to my website to see when the last update was installed, but it would be close to when the last update to the plugin was released as I keep my website up to date.

Dear Jeff,

From what we see, there is no 404 Page Not Found error on the link you have provided. Looks like the respond-2 is 05 but that is not a 404 error.

So we are guessing there was a temporary problem on your website and that was when it returned 404 error.
Thank you!