Hello!
I am having the exact same problem described in this support ticket: https://theeventscalendar.com/support/forums/topic/may-9th-update-conflict-with-wordpress/
I updated The Event Calendar, the site totally crashed, error code 500. I went into FTP deleted the plugin. Couldn’t reupload previous version via WordPress interface (it kept filing), so uploaded version 4.6.14 via FTP.
Then the filter bar stopped working. I updated that plugin, and now the filter bar plugin won’t activate.
I tried to upload the debug file, but your file uploader says I can’t uploaded files of this type (.txt)?
Thank you for your help on this!