Mine internet connection dropped out a twice in the last 3 days at 1AM for between 1 to 3 hours. Doesn't seem like a router fault, but more like some service update/upgrade?
The log viewing capabilities on the router is not optimal [cr@p] - you can only go forward/back one page at a time, you can't jump to a page, you can't download it, you can't search it so it took about 300 mouse clicks to get to the page for last outage on 22nd.
You can see in the log output below that there are no messages from 01:04:37 to 04:01:57 which is the length of that service outage (I know this because my Nest cameras and Access Points alerted me about loss of connectivity to cloud services during this time period). Although the log is set to debug level, it doesn't really give a clue as to where the issue is - did the router go down, did the line go down, only see that it acquires an IP address at the time the service is restored???
BTW: the log is full of a lot of messages "DNS name resolution failure (_bookmarkdavs._tcp.p51-bookmarks.icloud.com)" - what's that about?
22.08.2019 04:02:00 Info SYS TR-069 connectivity to (acs.talktalk.co.uk) has been closed
22.08.2019 04:01:57 Info DHCPC The WAN DHCP client IP address 2.100.207.20
22.08.2019 01:04:37 Error DNS DNS name resolution failure (_bookmarkdavs._tcp.p51-bookmarks.icloud.com)