Ics-File Issue

I have to import some ics-Files on two diffrent Club-Website. Before three weeks ago it was no Problem.

Today i want to import some ics-Files (see attachement) on the Frontend of http://www.jfg-teisenberg.de. No Event was shown. I found the importet events by "past events". I could not delete or modifie one of the Events. The start and enddate was 01.01.1970. I only can delete the events via phpmyadmin.

Whats wrong?

<code>
PHP Version : 7.0.20-nmm1
MySQL Version : 5.6.33-nmm1-log
Server Information : Linux dd18034 3.13.0-128-generic #177-Ubuntu SMP Tue Aug 8 11:40:23 UTC 2017 x86_64
Fix jQuery? : Yes
Load JEvents Bootstrap CSS? : Yes
Max Input Vars ? : 3000
Club code set? : No
User Agent : Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0
Joomla : 3.7.5
component_com_jevents : 3.4.42
component_com_jce : 2.6.19
module_mod_jevents_cal : 3.4.42
module_mod_jevents_custom : 3.4.42
module_mod_jevents_filter : 3.4.42
module_mod_jevents_latest : 3.4.42
module_mod_jevents_legend : 3.4.42
module_mod_jevents_switchview : 3.4.42
plugin_content_jevents : 3.4.42
plugin_finder_jevents : 3.4.42 (not enabled)
plugin_installer_jeventsinstaller : 3.4.42 (not enabled)
plugin_search_eventsearch : 3.4.42 (not enabled)
plugin_system_gwejson : 3.4.42
</code>