I will give you a bit more information what i did so far. I downloaded the sample .csv files provided in this document. I used LibeOffice Calc 5.1.5.2 to open the csv and add new entrys. I saved it as csv and tried to upload -> doesn’t work. A few weeks ago this worked on another page perfectly.
Okay, now i tried your solution and it doesn’t work either.
Also i changed the file encoding form “WinLatin” to “UTF-8” -> doesn’t work.
There is always an error during upload saying “Sorry this file type is not permitted for security reasons”
I think it has something to do with the new wordpress version denying to upload .csv for the plugin to use.
Worpress: 4.7.2 The Events Calendar: 4.4.1.1