Thanks for your quick response!
I also read about enabling php_openssl. Unfortunately I can’t access the php.ini in my shared hosting environment.
My provider only allows me to edit the following settings:
PHP Version
OPcache
add_default_charset
allow_url_fopen
allow_url_include
default_charset
display_errors
magic_quotes_gpc
magic_quotes_runtime
max_execution_time
max_input_vars
memory_limit
mod_rewrite
post_max_size
register_globals
session.auto_start
upload_max_filesize