I need a support

This is just the right place to get the support that you need, @gmnagaraj-gm. 

May I know the name of your bank and the error message you're getting when connecting it? I want to make sure that I'll be able to provide the correct info parallel to your issue. In the meantime, let's perform some troubleshooting steps.

For most general issues in QBO, clearing your browser's cache can do the trick. By clearing them, you can remove that historical data and access QuickBooks with a clean slate. 

Let's start by accessing your account through an incognito window to rule out the possibility of a webpage issue. You can refer to these shortcut keys to open an incognito window in all supported browsers:

• Chrome: Ctrl+Shift+N
• Firefox: Ctrl+Shift+P
• Safari: Command+Shift+N

If you can connect your bank, clear your browser's cache. You can also switch to a different supported browser to see if it has something to do with your browser.

You also have the option to manually import your transactions into QBO. I'd be glad to discuss this in detail. First, let's download the file from your bank's website. 

Here's how:

1. Sign in to your bank or credit card’s website.
2. Follow your bank’s instructions for how to download transactions to your computer. (Please take note that some banks call this WebConnect.)
3. Make sure the date range for the download is at least one day before your oldest transaction.
4. Download your transactions and save the file somewhere you can easily find it.

Then, review the file format and size before uploading it into QBO. The maximum file size is 350 KB. If your file is too big, shorten the date range and download your transactions in smaller batches. Also, let's make sure that you're using one of these formats:

• Comma-Separated Values (CSV)
• QuickBooks Online (QBO)
• Quicken (QFX)

Once done, here's how to start your upload if you've connected your account to online banking:

1. Go to the Transactions or Banking menu. Then, select the Banking tab.
2. Click the blue tile for the account you want to upload the transactions into.
3. In the Link account drop-down menu, select Upload from file.
4. Click Browse and select the file you downloaded from your bank, then click Next.
5. From the QuickBooks account drop-down menu, select the account you want to upload the transactions into and click Next.
6. Click the QuickBooks account drop-down menu and select the account you want to upload the transactions into. Then, click Next.
7. Follow the onscreen instructions. Match the columns on the file with the banking fields in QuickBooks, then select Next.
8. Select Let's go.
    

After you download your transactions in QuickBooks, you can review them in the For Review tab to make sure all of your data is downloaded. 

You can also refer to this link on how to fix common bank errors: What to do if you see a bank error or bank transactions won’t download.

You can always come back to this thread if you need more help with syncing your bank transactions. I'm determined to help you succeed.