This doesn't happen all the time, but I've had it happen a few times where I accept a match, and there won't be another match popup, no sound, and it will change from the orange of accepted to "you have declined the match". I don't know what's causing this. This is happening in the legacy client, but I don't know if it happens in the New client. Just thought I'd let you guys know.
An issue like that tends to be connection related, as the server never gets the information that you accepted (or at least not in time).
You can easily test for latency or packet loss by downloading the WinMTR Network Diagnostic Tool, then use that to run a traceroute to the following IP for NA (allow this to run for 5-15 minutes);
104.160.131.1
From there you can refer to the Connection Troubleshooting Guide for information on resolving these issues.
If you need assistance with that or the issue doesn't appear to be connection related, post on the Help & Support board and we'll try to help.
