The notification in the chat box says “Failed to connect to server,” which means there is a connection problem either locally or on the way to Blizzard. We know it’s not the match server, since others players connected to it and are talking to you from the match over chat.
Unfortunately, Blizzard doesn’t overturn bans for disconnections, but I highly recommend that you stop queuing for Competitive modes until you find the cause of the connection issue.
Using a WinMTR is a good step towards finding where the problem is happening.