Can you please provide advise for the lost connection to HMRC; first two VAT returns have been submitted MTD from QBO. Now I am unable to submit MTD VAT return. Thanks

Hello Radulova 76-gmail, 

Welcome to the community page, 

Have you tried disconnecting MTD and reconnecting git in the main settings, 

Cogwheel>account and settings>advanced> MTD> learn how to disconnect-follow the steps then once disconnected, click on learn how to reconnect 

see if that resolves your issue