IPSec is an encryption protocol that is negotiated to protect the data between your laptop and a security system in your work, usually the firewall.
There could be multiple causes for issues here and certainly poor connectivity is a candidate but if your other internet services seem okay (try streaming some HD video from Youtube and see if it plays okay) then it may be a connection at your work side or config problem.
You can test if it's your WiFi by connecting directly to your router with an Ethernet cable if you have one and a spare port, if it works okay then it's likely a WiFi issue.
Best bet is to try it when you are in the office and see if it keeps happening, if so then speak to your IT department.