reconnecting my bank account

Hello, @Sarah_HM. I'm here to ensure you'll be able to reconnect your bank to QuickBooks Online (QBO).
 

Banking error 377 means QuickBooks is unable to download your transactions. After signing in to Timberland, go back to your QBO account and update your online bank connection. 
 

Here's how:
 

1. Log in to your QBO account.
2. Select Transactions from the left menu.
3. Go to the Bank transactions section.
4. Click Update Now from the Let's fix this bank connection banner.
5. Follow the on-screen steps. When prompted, log in to your bank account.
6. Once done, QuickBooks can download transactions again.
    

In addition, once you've successfully connected your bank to QBO, I'd recommend categorizing and matching your entries to ensure your financial records are all accurate.
 

Please don't hesitate to leave a comment in this thread if you need further assistance with connecting your bank to QBO. Our team is always here to back you up. Have a good one.

I was able to reconnect my bank account to Quickbooks but there is a full month of transactions missing. How do I ensure all the transactions imported? My last date reconciled is 3/31 but any transaction from 4/1-5/15 isnt showing

I can see why you're unable to download transactions from the 1st of April to mid-May, @Sarah_HM. With this, I'll share with you the details of the occurrence and provide a way to get them into your bank feeds.

Most bank institutions let you download 90 days' worth of transactions after you connect your online banking. This explains why transactions that are older than the specified number of days aren't available on your bank feeds. To sort it out, we'll have to manually import them via CSV so you can start categorizing them.

Review your file's formatting to prevent any possible issues. After that, proceed to the steps below to start uploading them:

1. Go to the Transactions menu and select Bank Transactions.
2. Tap your bank’s tile where you want to upload the file.
3. Tap the Link account dropdown and select Upload from file.
4. Hit the Drag and drop or select files and then select the file you downloaded from our bank. Then, click Continue.
5. Follow the onscreen procedures to match the columns on the file with the correct fields. Then, select Continue.
6. Select the transaction you’d like to import and select Continue. After that, select Yes.
7. Lastly, click Done.

If you're done working on your transactions, you can consider categorizing and reconciling them afterward to keep your records accurate and immediately spot any possible discrepancies in the account. 

Please don't hesitate to post to the Community if you require additional assistance with banking. We're available 24/7 to lend an extra hand to help you. Have a good one!