Suggest to have a basic check.
1. Run the version check
in the admin => Version (in the upper right hand corner)

If you have the cURL running and in the report you will find a section similar as below.
curl
CURL support enabled
CURL Information libcurl/7.14.0 OpenSSL/0.9.8b zlib/1.2.3
2. If the above passed, then check your cURL setting,
in admin => Configuration

there are 2 options as below, please configure the right settings.

cURL Proxy Status False (it should be set to true to enable it)
cURL Proxy Address (it should be set according to your server settings)

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