pfSense

pfSense 2.3.2-RELEASE

We have many site-to-site vpn's configured in our pfSense, an i386 vm running on vmware.
Three of them suddenly begin to fall, one after the other, 2 a.m. the first one, 3 a.m. the second one, at 6 a.m. the third one falls unrecoverable.
When trying to disconnect and connect again, any of them, on the ipsec log we have:

Apr 19 05:15:34 charon: 12[IKE] <7152> found 1 matching config, but none allows pre-shared key authentication using Main Mode

Apr 19 05:15:34 charon: 12[ENC] <7152> generating INFORMATIONAL_V1 request 4141821673 [ HASH N(AUTH_FAILED) ]

The only solution that we found, was to reboot the vm, completely, after what they started to work OK, just like the rest of the site-to-site vpn configurations.

None of the psk was changed, no change was made since weeks ago.

I'm submitting one of the configurations that failed (that at 6 a.m.):

conn con11000
fragmentation = yes
keyexchange = ikev1
reauth = yes
forceencaps = no
mobike = no

rekey = yes
    installpolicy = yes
    type = tunnel
    dpdaction = clear
    dpddelay = 10s
    dpdtimeout = 60s
    auto = add
    left = 1xx.xx.xx.126
    right = 1xx.xxx.xxx.6
    leftid = 1xx.xx.xx.126
    ikelifetime = 28800s
    lifetime = 3600s
    ike = aes256-sha1-modp1024!
    esp = aes256-sha1-modp1024!
    leftauth = psk
    rightauth = psk
    rightid = 1xx.xxx.xxx.6
    aggressive = no
    rightsubnet = 1x.xxx.xx.7
    leftsubnet = 1x.xxx.0.0/16

Any help, greatly appreciated.