UnityWebRequestTexture Unable to Load From Directories Containing '#' or '+' Characters

I'm using UnityWebRequestTexture to load images from my file system into my game. Here is my code:

 private IEnumerator ImageLoadCoroutine(int i)
     {
             GameObject imgObj;
             Texture2D imageTex = null;
             //string activeDir = fileList[i];
             //activeDir = activeDir.Replace("+", "+"); // Does not fix issue!
             //using (UnityWebRequest uwr = UnityWebRequestTexture.GetTexture(activeDir))
             using (UnityWebRequest uwr = UnityWebRequestTexture.GetTexture(fileList[i]))
             {
                 yield return uwr.SendWebRequest();
 
                 if (uwr.isNetworkError || uwr.isHttpError)
                 {
                     //  "+" dirs have HttpError
                     Debug.Log(uwr.error + "(" + uwr.isNetworkError + ", " + uwr.isHttpError + ")");
                 }
                 else
                 {
                     // Get downloaded asset bundle
                     imageTex = DownloadHandlerTexture.GetContent(uwr);
                 }
             }
             imgObj = Instantiate(imagePrefab);
             imgObj.transform.SetParent(imageContainer.transform);
             imgObj.transform.localPosition = Vector3.zero;
             imgObj.transform.localRotation = Quaternion.identity;
             imgObj.transform.localScale = Vector3.one;
             imgObj.GetComponent<RawImage>().texture = imageTex;
             imgObj.GetComponent<RawImage>().enabled = false;
             imgObj.GetComponent<BoxCollider>().enabled = false;
         imagesLoaded++;
         imageList[i] = imgObj;
 
     }

However, when I try to load images from directories containing the '+' or '#' characters (i.e. "C:\Users\MyUser\Documents\Unity Projects\The+++Folder"), I get the HttpError: "HTTP/1.1 404 Not Found" Directories containing other special characters like @, &, or = work fine. Using the Replace function to replace the characters with their character entity reference code (i.e., replacing all instances of "+" with "& plus ;") did not fix the problem.

What is the source of this issue, and is there a way around it? I'd rather not be arbitrarily restricted in which valid folder names actually work with my program.

Thanks!