Downloading apps error with fresh nextcloudpi install

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Nextcloud version (eg, 12.0.2):14.0.3.0
Operating system and version (eg, Ubuntu 17.04): raspberry pi 3 with nextcloudpi
Apache or nginx version (eg, Apache 2.4.25):
PHP version (eg, 7.1):7.2.9

When i try to download new apps or even when i try to update the calendar extension i got this error message:

GuzzleHttp\Exception\ConnectException: cURL error 6: Could not resolve host: github-production-release-asset-2e65be.s3.amazonaws.com (see http://curl.haxx.se/libcurl/c/libcurl-errors.html)

Any help will be appreciated