Very slow initial connection

[Cosma Papouis1709152067]

Here's a conundrum for you. I have upgraded some Win 7 PC's to Win 10. All works fine except for one PC where the Citrix connection to an outside service provider is unbelievably slow to connect. I have no access to the servers. For some reason, after you log in to the netscaler and click on the published app it takes ages (and I mean ages) for the app to come up. I got fed up on one of the machines and did a system refresh and now it works fine. One of the Other PC's, that was working fine is now displaying the same problems. I have uninstalled, reinstalled copied reg entries and program files folders, but no good. I am reluctant to refresh this one as it has a pile of software that I am going to have trouble finding (as it is so old). Luckily I had an office 2007 CD for the other PC. Any idea's what could be causing this? In a previous life I built and used a Citrix farm, but have never seen anything like it.