Please check below
I have observed that the connection is instant in our environment if the user unchecks the "Automatically Detect Settings" for the proxy option under Internet Explorer. Even if the user does not have a proxy server, the proxy settings may be set in Internet Explorer. This is where the issue resides and the reason why some clients exhibit the problem (where the proxy settings are set).
When reviewing the GlobalProtect client logs, the user might see:
(T2760) 12/09/13 09:43:16:863 Debug (4651): Auto detect proxy for host vpn.domain.com
(T2760) 12/09/13 09:43:37:908 Debug(4662): CPanMSService::SetProxyForHost:
fAutoDetect: 1 url: proxy: bypass: url: https://vpn.domain.com/ returned proxystr:
In the example above, it takes 31 seconds for the Windows system to detect the proxy setting. The result is no proxy for https://vpn.domain.com/, even if the url is opened.
Please check the GPS logs from the client and look for below logs
Uncheck the "Automatically Detect Settings" for the proxy option in Internet Explorer to speed up GlobalProtect connections. With this setting enabled, the GlobalProtect client reads the proxy settings in Internet Explorer even if there is no proxy server.