Intermittently cant connect to VPN from Laptop, but always works from iPhone Ive got a few VPNs setup to different LANs, these are all IPSEC over LT2P connections and i manage them by OSX's built in VPN client inside system preferences > network. 

Sometimes the VPNs will work fine, but sometimes i notice that i can not connect to any of my VPNs, and i get an error as per the below screenshot. Becuase they work fine sometimes, but wont connect other times i dont think its anything to do with credentials. Ive also noticed that none of the 6 VPNs i have will work, so it seems like its something to do with my laptop rather than the VPNs themselves. 

Whats strange is that the VPNs themselves seem to be working fine, as if i connect to them on my iPhone running iOS12 they will connect. 

Any ideas why my laptop running OSX 10.11 wouldnt work ?
Why don't you upgrade to the latest version.
Did you try turning off your wifi on Mac and turning it on again? After that try connecting one by one. You will find which one is causing the issue. Try killing them as well.
Try restarting your machine if 1 and 2 don't work.
Worst case, remove all the configurations, add one by one and observe over a period of time.