[TYPO3-english] Update Extension List: Could not access remote resource

[Bastian Holzem]

I try to update the extension list but get error
"Could not access remote resource https://repositories.typo3.org/mirrors.xml.gz."

i already tried:
# [SYS][curlUse] = 1
# empty Cache
# raise PHP Limits
# delete Temp Folder
# SQL Debuging = 0

I using xampp, php 7.0 and typo3 7.6.2
ironically in works on another typo3 installation (also 7.6.2) on my xampp hosting 
what could couse the error?

Thank you for your help

Danke für eure Hilfe