@Kevin_Z I noticed my TP-Link DDNS wasn't active when I tried to use my Wake-On-Lan over the internet. My address wasn't even responding to pings. Then I went to the router settings, logged in with my local password (as I usually do) and found out I was logged out of TP-Link Cloud -- both on the router itself and on the DDNS settings (though I guess it's the same thing).
So I logged back into TP-Link Cloud and my DDNS came back online.
But the next day I tried using Wake-On-Lan over the internet again and nothing happened. Logged into the router (again with my local password) and found out I had been logged out of TP-Link Cloud once again.
This kept happening over and over.
Now I tried logging into the router not with my local password, but with my TP-Link Cloud ID and everything seems fine. DDNS is online, Wake-On-Lan works as it should.
I think that, all in all, it's a very awkward situation. If I log into the router using my local password and THEN log into TP-Link Cloud, the connection to the latter goes down after a while. But if I log into the router using my TP-Link Cloud ID directly, it works.
Why, then, are there two separate login methods, and one of them is contained within the other AND works differently depending on how I use it?
There shouldn't be an option to log into TP-Link Cloud ID after logging locally, if that connection is going to go down in a few hours or minutes. It should be one or the other, local or cloud. Or at least there should be a warning of some sort.
Anyway, it all seems to be working fine now -- despite the "long" road I had to make work of a simple thing like a cloud account.
Thanks!