USG310 VPN Issue connecting

Zodiac13

Hey guys new IT guy here. I just got out of an internship and need some help. New boss came in and changed all the VPN settings on our firewall and now no one can connect. I set it up about a year ago but never had to go back and figure it well we have been out of office due to the pandemic and well my VPN was a godsend as we could all work from home. We hire this guy about 5 months ago and he breaks it! He said to me "Well I just changed one thing and then changed it back" he is the new IT manager.  I have looked over it and to me seems like he messed with the L2TP pool but im not sure i wish I had more time with setting these up. Whatever he did messed up connection to all our offices and well id like to be the hero here he has been working on this for over a month and it has not been resolved. I get the error -16015 when I try to connect. any ideas what I can do to get this back online?

Zyxel_Charlie

@Zodiac13
Regarding to the VPN issue related with error message -16015, you may check the configuration and parameters on the PC(L2TP client) with following thread first.
https://community.zyxel.com/en/discussion/2625/zywall110-error-number-16015-error-message-dial-a-dynamic-tunnel-has-failed-for-crypto-map/p1