Navigating to decoded URL doesn't elicit the same action as navigating to the encoded URL

Trying to understand why pasting the first link works but not the second one.

Breakdown of the URL, for a clearer view:

Encoded version: [works]

http%3A%2F%2FsomeSite.com
%2FDownload.ashx
%3Frequest
%3DIL7zxW6ETqiYU6cThSNKL8MpY
%252bCRIVFZAVhd8DYPG85C1Uhdd
%252f2hqqmoObeNmuS3dg4bDgGBb0kUUxGZhej89kTaLBHBXS
%252bq3tlaEk2uMEcbWlUZzZQs00sirwZ2IvAvoSpU7HC3N1FaYSNciQ4iHNNmTU
%252f6uMypNlPOJ6enlbZ1OrrYODkaMRdRfGKEba
%252brusdryM4gp
%252bopi1a0gNuMQVCtj
%252bAvDcgXGOcZPNhPAnE
%253d&version=Ma88r6Z6t2JQcnVhVXgp0A%3D%3D

Decoded version: [doesn't work]

http://someSite.com
/Download.ashx
?request=
IL7zxW6ETqiYU6cThSNKL8MpY
+CRIVFZAVhd8DYPG85C1Uhdd
/2hqqmoObeNmuS3dg4bDgGBb0kUUxGZhej89kTaLBHBXS
+q3tlaEk2uMEcbWlUZzZQs00sirwZ2IvAvoSpU7HC3N1FaYSNciQ4iHNNmTU
/6uMypNlPOJ6enlbZ1OrrYODkaMRdRfGKEba
+rusdryM4gp
+opi1a0gNuMQVCtj
+AvDcgXGOcZPNhPAnE
=&version=Ma88r6Z6t2JQcnVhVXgp0A==

If I paste the first link in the browser - it works. A file download automatically starts.
If I paste the second link in the browser - page says Bad request.

Can anyone clarify it for me why the second one doesn't work?

Solution

Quoting the URLencodetag:

To “URL encode” or “percent encode” text means to encode it for use in a URL. Some characters are not valid when used as-is in URLs, and so much be URL-encoded (percent-encoded) when appearing in URLs.

The encoding was used for a reason, here because the base64 values for the request and version parameters contains +, / and = which have their own meaning in URLs and therefore need to be URL-encoded.