Do you host your own Citrix Farm? Do you have external access available through ADC Gateway (NetScaler)? Are clients accessing Storefront internally? DO clients connect via Web or Services (Receiver plug-in configuration)
Citrix Receiver 12.4 For Mac
If so the issue is most likely incompatible encryption at Storefront / ADC Gateway for the client. I hope you are not using Web Interface instead of Storefront, as this only supports TLS 1.0 and some clients will most likely fail.
Does Citrix Offer A Removal Tool For Citrix Receiver For Mac Windows 10
I recently had to download Citrix Receiver for work and though I have removed the application from my computer, it still shows in the icon in the menu bar any time the computer is restarted. I've received the applications file, as well as libraries within Finder. If I do a spotlight search for Citrix, there are no hits. Beginning August 2018, Citrix Receiver will be replaced by Citrix Workspace app. While you can still download older versions of Citrix Receiver, new features and enhancements will be released for Citrix Workspace app. Citrix Workspace app is a new client from Citrix that works similar to Citrix Receiver and is fully backward-compatible with. Let’s get down to the easiest and most efficient method to completely uninstall Citrix Receiver from your Mac. We strongly suggest that you use iMyMac PowerMyMac, which is a powerful program that can help you maximize the usage of your Mac, and yes, uninstalling is among that list.
Storefront supports all TLS versions so this should be in use and Web Interface retired.
Latest ADC Gateway builds have all latest TLS versions built in as well. Also check/test Cipher suite configuration here.
Are your clients up to date with Windows updates? Out of date clients/browsers (when connecting through Web) can have encryption issues connecting through the gateways.