Site to site VPN Issues after adding second site

[BlakeRichardson]

Last year I configured a site to site VPN between to MX located in different ORG's so a "Non Meraki VPN" This has worked well with no issues. I'll refer to them as site A and B

Then last week I added a second "Non Meraki" site to site VPN to one of the MX units that connects to site C. This connection works well but now the original A to B link has gone down at the same time the new connection stood up.

Looking at the event log for site B the last log is msg: <remote-peer-2|1277> deleting IKE_SA remote-peer-2[1277] between REDACTED

Both A and B are running the same firmware ( 18.107.2)

[alemabrahao]

Have you tried with another MX version?

[BlakeRichardson]

They were working with the current firmware but no as the dashboard will not allow me to rollback firmware because they were upgraded over a month ago and they are running up to date firmware.