Hi Katharina,
There are several things you can do, if you are a little familiar with Joomla.
1) deactivate all template override for JEM in:
/templates/cassiopeia/html/com_jem
/templates/cassiopeia/html/mod_jem
/templates/cassiopeia/html/mod_jem_banner
etc.
(to deactivate them, just rename the folder like "com_jemX"
2)
0 3 arguments are required, 2 givenCall stackFunction Location1 () JROOT\libraries\src\Language\:281
2 sprintf() JROOT\libraries\src\Language\:281
3 Joomla\CMS\Language\Text::sprintf() JROOT\plugins\editors\codemirror\layouts\editors\codemirror\:67
The first lines of the error log says that there is a problem with the language files. Do you use language files other than English?
Fo yes, please remove all old language files
/language/YOUR-LANG/com_jem.*
/administrator/language/YOUR-LANG/com_jem.*
"YOUR-LANG" is the code for your language, like de-DE for German, fr-FR for French etc.
Then reinstall JEM 4 language files (you find them here:
www.joomlaeventmanager.net/download
)
Save and then deactivate the language overrides (if you have any) in /language/overrides/YOUR-LANG.override.ini by renaming the file e.g. to YOUR-LANG.override.iniX
Check to see if the error persists.
