I searched for the error on google and found the following
It seems like when the setup is not correct you get the error you mentioned.
Hope this helps.
This indicates mismatch with remote site.
Check proposals for IKE and IPSec. Make sure traffic is not NATed.
If you are using cisco at remote end, select DH-group 'no-pfs' for the proposal.
If tunnel is up and working, these messages may be during the negotiation.
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