Yes, I installed one pictures viewer but removed it after one week.
I don't see any relation between some software installation with web login reliability.
I was referring to any internet or internet related software. I do not know what browser you are running and I did not know if you had recently updated it. Further, I have seen some security software prevent opening of some web pages on my machine. Nothing like the Dxo support page, but other pages.
Are you running Safari? If so, do you have any (Safari related) plugins installed and running? If so have you tried to turn them off to see if that is the issue? If you have more than one browser on your system have you tried to see if you have this problem with all of them?
Since I do not see this on my machine I am trying to think of what might be an issue. I have Safari 10.0.3 running with Sierra 10.12.3 and am not seeing this problem on any of my Macs. I have not tried it with an iOS device.