Import Customer without error-log and protocol

I am trying to import customer, so I downloaded the template with minimum data, changed it and tried to import. The result is as following:

About the data:

Download

Start entering data below this line
“CUST-2018-00001” CUST-.YYYY.- P… GmbH Company PotentialGroup CH-4000 “342b1a93f7” John Sales

Changed to

Start entering data below this line
CUST-.YYYY.- Test GmbH Company PotentialGroup CH-4000 “342b1a93f7” John Sales

So I only deleted “CUST-2018-00001” and changed the company-name to Test GmbH.

Try a .csv file and not .xlsx type. Also, what is the error?

My provider installed the dev-version, now with the master-version it is o.k.!

@bergfrieden
Plz screen shot of erro message.