Are all 3 systems located under the same address?I'm using 3 different computers: An old Windows 7 PC, a 5-year-old Windows 10 laptop and a 2-year-old Windows 10 laptop. It seems to be an issue on all of them, though maybe the latter one less so.
Do they have the same configuration somehow?
Is there the same (software) firewall and/or the same router/hardware firewall inbetween?
Did you try to use the systems with browsers in safe mode without any add-ons/extensions activated?
Did you run a virus scanner and/or malware/spyware defender to see if something is there which should not be?
There are many more questions to be asked because finding out the golden question is not so easy.
But for the start those questions are usefull to isolate some parts of the system such as software/hardware.