Issue in sending SMS via sp_OAMethod in MS-SQL 2008

Dear All,
Hi I am using below given procedure to send SMS from Ms-SQL. it's working fine till yesterday night. But, today I am getting following error: -

-2146697212
Msg 50000, Level 16, State 1, Procedure pr_SendSmsSQL, Line 61
sp_OAMethod Send FAILED!
I added "sp_OAGetErrorInfo" to know the exact error then it shows me below given message: -
----------
Error Source Description
msxml3.dll Unable to connect to the target server.
----------

Please guide how to solve this issue. The same code is running properly on another SQL Server.

Store Procedure code : -
------------------------------
USE [TEST]
GO
/****** Object: StoredProcedure [dbo].[pr_SendSmsSQL] Script Date: 03/30/2012 13:10:52 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

/*
Purpose : To send SMS from SQL.

declare @sResponse as varchar(1000)
exec pr_SendSmsSQL '1234567891','This Is a Test SMS From SQL Server - Regards, BSethi24',''
print @sResponse

*/
ALTER Procedure [dbo].[pr_SendSmsSQL]
@MobileNo varchar(12),
@smstext as varchar(300),
@sResponse varchar(1000) OUT
as
BEGIN

Declare @iReq int,@hr int
Declare @sUrl as varchar(500)
DECLARE @errorSource VARCHAR(8000)
DECLARE @errorDescription VARCHAR(8000)



-- Create Object for XMLHTTP
EXEC @hr = sp_OACreate 'Microsoft.XMLHTTP', @iReq OUT
print @hr
if @hr <> 0
Raiserror('sp_OACreate Microsoft.XMLHTTP FAILED!', 16, 1)


set @sUrl='http://122.22.12.12/smsportal/sends...d=BSethi24&mobileno=#MobNo#&messagetext=#Msg#'


set @sUrl=REPLACE(@sUrl,'#MobNo#',@MobileNo)
set @sUrl=REPLACE(@sUrl,'#Msg#',@smstext)

print @sUrl
-- sms code start


EXEC @hr = sp_OAMethod @iReq, 'Open', NULL, 'GET', @sUrl, true
print @hr
if @hr <> 0
Raiserror('sp_OAMethod Open FAILED!', 16, 1)

EXEC @hr = sp_OAMethod @iReq, 'send'
select @iReq
print @hr
if @hr <> 0
Begin
EXEC sp_OAGetErrorInfo @iReq, @errorSource OUTPUT, @errorDescription OUTPUT
SELECT [Error Source] = @errorSource, [Description] = @errorDescription
Raiserror('sp_OAMethod Send FAILED!', 16, 1)
end
else
Begin
EXEC @hr = sp_OAGetProperty @iReq,'responseText', @sResponse OUT
print @hr

insert into s_SmsLog (Id,Mobile_No,SMSText,SMSResponse,Created_By,Created_Date,Modified_By,Modified_Date)
values(0,@MobileNo,@smstext,@sResponse,'System',GETDATE(),null,null)
End


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