Invalid length for a Base-64 char array or string in decryption

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C#

ASP.NET

Hello,

I am working with asp.net webapplication. I uploaded my project files on live server. While browsing i am getting below error in some systems only. And in some other systems its working fine. Can you suggest me any solution for this problem

Exception : Invalid length for a Base-64 char array or string

Above exception is coming in below code

protected void btnGo_Click(object sender, EventArgs e)
        {
            try
            {
                //decrypting email
                string email = GlobalMethods.Decrypt(Request["Email"].ToString(), true);
                //getting entered user name
                string user = txtUser.Text;
                //getting entered dob
                DateTime DOB = DateTime.ParseExact(txtdob.Text, "dd/MM/yyyy", CultureInfo.InvariantCulture, DateTimeStyles.None).Date;
                
                //validating in db
                DataTable dt = bll.getUser_vaild(email, user, DOB);
                //if exists display next screen to update password
                if (dt.Rows.Count > 0)
                {
                    this.ClientScript.RegisterStartupScript(this.GetType(), "edit", "document.getElementById('view2').style.display='block';", true);
                }
                else
                    ScriptManager.RegisterStartupScript(this, this.GetType(), "temp", "<script language='javascript'>alert('Invalid details');</script>", false);
            }
            catch (Exception ex)
            {
                ErrorLogger.WriteLogFile(HttpContext.Current.Request.UserHostAddress, this.GetType().Name, System.Reflection.MethodBase.GetCurrentMethod().Name, ex.Message.ToString());
                ScriptManager.RegisterStartupScript(this, this.GetType(), "temp", "<script language='javascript'>alert('" + ex.Message + "');</script>", false);
            }
        }

Below are Encrypt, Decrypt methods :

public static string Encrypt(string toEncrypt, bool useHashing)
{
byte[] keyArray;
byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(toEncrypt);

System.Configuration.AppSettingsReader settingsReader =
new AppSettingsReader();
// Get the key from config file

string key = (string)settingsReader.GetValue("SecurityKey",
typeof(String));
//System.Windows.Forms.MessageBox.Show(key);
//If hashing use get hashcode regards to your key
if (useHashing)
{
MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
//Always release the resources and flush data
// of the Cryptographic service provide. Best Practice

hashmd5.Clear();
}
else
keyArray = UTF8Encoding.UTF8.GetBytes(key);

TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
//set the secret key for the tripleDES algorithm
tdes.Key = keyArray;
//mode of operation. there are other 4 modes.
//We choose ECB(Electronic code Book)
tdes.Mode = CipherMode.ECB;
//padding mode(if any extra byte added)

tdes.Padding = PaddingMode.PKCS7;

ICryptoTransform cTransform = tdes.CreateEncryptor();
//transform the specified region of bytes array to resultArray
byte[] resultArray =
cTransform.TransformFinalBlock(toEncryptArray, 0,
toEncryptArray.Length);
//Release resources held by TripleDes Encryptor
tdes.Clear();
//Return the encrypted data into unreadable string format
return Convert.ToBase64String(resultArray, 0, resultArray.Length);
}
public static string Decrypt(string cipherString, bool useHashing)
{
byte[] keyArray;
//get the byte code of the string

cipherString = cipherString.Replace(' ', '+');

byte[] toEncryptArray = Convert.FromBase64String(cipherString);

System.Configuration.AppSettingsReader settingsReader =
new AppSettingsReader();
//Get your key from config file to open the lock!
string key = (string)settingsReader.GetValue("SecurityKey",
typeof(String));

if (useHashing)
{
//if hashing was used get the hash code with regards to your key
MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
//release any resource held by the MD5CryptoServiceProvider

hashmd5.Clear();
}
else
{
//if hashing was not implemented get the byte code of the key
keyArray = UTF8Encoding.UTF8.GetBytes(key);
}

TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
//set the secret key for the tripleDES algorithm
tdes.Key = keyArray;
//mode of operation. there are other 4 modes.
//We choose ECB(Electronic code Book)

tdes.Mode = CipherMode.ECB;
//padding mode(if any extra byte added)
tdes.Padding = PaddingMode.PKCS7;

ICryptoTransform cTransform = tdes.CreateDecryptor();
byte[] resultArray = cTransform.TransformFinalBlock(
toEncryptArray, 0, toEncryptArray.Length);
//Release resources held by TripleDes Encryptor
tdes.Clear();
//return the Clear decrypted TEXT
return UTF8Encoding.UTF8.GetString(resultArray);
}

Thanks,