Issues in Receive Payments API V2 with .onion site

[mgscreativa]

Hi! I am trying to get my Receive Payments API V2 integration to work on an .onion site but I get an error: "Error creating payment address on Blockchain: Malformed callback URL"

If I try the very same implementation on a .com site, it works.

Is there any special treatment for .onion sites in the callback API GET param?

I'm contacting the API like this using PHP:

curl_setopt($curl, CURLOPT_URL, 'https://api.blockchain.info/v2/receive?xpub='.$this->payment_params->xpub.'&callback='.urlencode($callback_url).'&key='.$this->payment_params->api_key);

Thanks in advise!