Unable to process browser request when downloading a PDF

[Dzeri96]

Describe the bug
I'm trying to download a PDF from https://www.mdpi.com/1996-1944/12/18/2995/pdf, but CloudProxy throws an error.

To Reproduce
Make the following request:

{
    'cmd': 'request.get',
    'url': 'https://www.mdpi.com/1996-1944/12/18/2995/pdf',
    'userAgent': 'Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:95.0) Gecko/20100101 Firefox/95.0',
    'download': True
} # Python syntax

Expected behavior
A PDF is downloaded as a byte stream

Desktop (please complete the following information):

• OS: Linux
• Browser Any
• Version 2.1.1

Additional context
This is the stack trace:

cloudproxy_1  | 2022-01-07T23:13:16.548Z INFO REQ-0 CloudProxy v2.1.1 listening on http://0.0.0.0:8191
cloudproxy_1  | 2022-01-07T23:13:24.087Z INFO REQ-1 Incoming request: POST /v1
cloudproxy_1  | 2022-01-07T23:13:24.089Z INFO REQ-1 Params: {"cmd":"request.get","url":"https://www.mdpi.com/1996-1944/12/18/2995/pdf","download":true}
cloudproxy_1  | 2022-01-07T23:13:24.090Z DEBUG REQ-1 Launching headless browser...
cloudproxy_1  | 2022-01-07T23:13:24.390Z DEBUG REQ-1 Adding custom headers: {}
cloudproxy_1  | 2022-01-07T23:13:24.390Z DEBUG REQ-1 { headers: [Function (anonymous)] }
cloudproxy_1  | 2022-01-07T23:13:24.397Z DEBUG REQ-1 Navigating to... https://www.mdpi.com/1996-1944/12/18/2995/pdf
cloudproxy_1  | 2022-01-07T23:13:24.407Z DEBUG REQ-1 {
cloudproxy_1  |   headers: {
cloudproxy_1  |     'upgrade-insecure-requests': '1',
cloudproxy_1  |     'user-agent': 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.113 Safari/537.36',
cloudproxy_1  |     'accept-language': 'en-US,en;q=0.9'
cloudproxy_1  |   }
cloudproxy_1  | }
cloudproxy_1  | 2022-01-07T23:13:25.506Z ERROR REQ-1 Error: net::ERR_ABORTED at https://www.mdpi.com/1996-1944/12/18/2995/pdf
cloudproxy_1  |     at navigate (/home/node/cloudproxy/node_modules/puppeteer/lib/FrameManager.js:95:23)
cloudproxy_1  |     at processTicksAndRejections (node:internal/process/task_queues:93:5)
cloudproxy_1  |     at async FrameManager.navigateFrame (/home/node/cloudproxy/node_modules/puppeteer/lib/FrameManager.js:70:21)
cloudproxy_1  |     at async Frame.goto (/home/node/cloudproxy/node_modules/puppeteer/lib/FrameManager.js:295:16)
cloudproxy_1  |     at async Page.goto (/home/node/cloudproxy/node_modules/puppeteer/lib/Page.js:485:16)
cloudproxy_1  |     at async resolveChallenge (/home/node/cloudproxy/dist/routes.js:71:20)
cloudproxy_1  |     at async browserRequest (/home/node/cloudproxy/dist/routes.js:285:22)
cloudproxy_1  |     at async request.get (/home/node/cloudproxy/dist/routes.js:325:9)
cloudproxy_1  |     at async Object.Router [as default] (/home/node/cloudproxy/dist/routes.js:346:16)
cloudproxy_1  |   -- ASYNC --
cloudproxy_1  |     at Frame.<anonymous> (/home/node/cloudproxy/node_modules/puppeteer/lib/helper.js:94:19)
cloudproxy_1  |     at Page.goto (/home/node/cloudproxy/node_modules/puppeteer/lib/Page.js:485:53)
cloudproxy_1  |     at Page.<anonymous> (/home/node/cloudproxy/node_modules/puppeteer/lib/helper.js:95:27)
cloudproxy_1  |     at resolveChallenge (/home/node/cloudproxy/dist/routes.js:71:31)
cloudproxy_1  |     at browserRequest (/home/node/cloudproxy/dist/routes.js:285:28)
cloudproxy_1  |     at processTicksAndRejections (node:internal/process/task_queues:93:5)
cloudproxy_1  |     at async request.get (/home/node/cloudproxy/dist/routes.js:325:9)
cloudproxy_1  |     at async Object.Router [as default] (/home/node/cloudproxy/dist/routes.js:346:16)
cloudproxy_1  | 2022-01-07T23:13:25.507Z ERROR REQ-1 Unable to process browser request