Hello,
I work in a DSL team, and This issue is ISP related. Or at least with the DSL line itself.
As you can notice, the Noise Margin during the outage gets too low:
Noise Margin: -2.5 dB 31.0 dB
While during normal operation it stays between 10 and 31 which is a perfect value:
Noise Margin: 11.0 dB 31.0 dB
Have your ISP check the line from your site, and also, a good workaround in the meantime would be replacing the Microfilter that your DSL line should be using... if you're not using one, i'd suggest you buying one and installing it on the DSL line.
Pls rate if helpful