This time the behavior is a bit different. Last time the log showed that networking call timed-out after 20 seconds. This time it failed quickly, in 2 seconds.
The channels involved, 13.1 last time, and 10.1 this time had different IP addresses. I think IP address change might be the cause. Have you been resetting your LAN?
The new log shows that channel 10.1 is using an URL of
http://192.xxx.xxx.3:5004/auto/v10.1 (with the last part of IP address being 3). Previously the last part of the IP was 13.
You can check if your FLEX 4K device's IP address currently matches the IP address of channel 10.1. If they don't match, recording will fail. This is an oversight on my part. I had actually added code so that playing a channel live would dynamically correct IP address discrepancy. I should have done the same for recording too. I will do it tomorrow.
In the mean time you can first confirm whether IP address of the device has changed. Another way to test is to simply try watching the problem channel live, without trying to record. If that is successful, check the channel details and see if MC automatically corrected the IP address.