I appreciate you for chiming in on this thread, Riccardo. I'll be happy to share some troubleshooting steps so you can connect to His Majesty's Revenue & Customs (HMRC) in QuickBooks Online (QBO).

If you're getting the error "We can't connect to HMRC right now," it's possible that:

• The credentials you used to connect QBO to HMRC aren't authorised to file a Value Added Tax (VAT).
• There are no open obligations with HMRC.
• The current VAT return period date in QBO has not yet ended or doesn't match with HMRC.
• The VAT registration number is incorrect.

To rectify this, ensure you utilize the correct login credentials when submitting your VAT return. Additionally, verify the filing period in QBO if it matches the HMRC. Then, review if the VAT registration number is accurate. To do that:

1. Go to Taxes and select the VAT tab.
2. Click the Edit VAT dropdown button, then select Edit settings.
3. On the Edit HM Revenue & Customs (VAT) Settings page, ensure you have the correct 9-digit VAT registration number. This field should only contain a number format without letters or spaces. 
4. Click Save.

Once done, reconnect to the HMRC. If the issue persists, refresh the connection by disconnecting and reconnecting the Making Tax Digital (MTD). Here's how: 

1. Go to the Gear icon and select Account and Settings.
2. Click the Advanced tab.
3. Go to the Making Tax Digital section and click Learn how to disconnect.
4. Follow the onscreen procedure to finish the process.
5. Reconnect your MTD and resume to submit your VAT returns.

Moreover, view the list of transactions that are included in each box on the VAT return by running a VAT Detail report in QBO.

Let me know whenever you have questions concerning VAT filing. The Community is here to help anytime. Keep safe, and have a great rest of the day!