OmniFocus 1.8.1 for iPhone is now available, fixing these erroneous sync error messages.
Solution was to remove OF, restart,
reload OF, restart, set sync and OF was working again.
"UNABLE TO SYNCRHONIZE DATABASE WITH SERVER. The certificate for this server is invalid. You might be connecting to a server that is pretending to be
which could put your confidential information at risk. Would you like to connect to the server anyway?"
Re-installed 1.8, no go.
Completely removed OF and restarted, iPhone and Mac.
Re-installed 1.8.1, no go.
Re-set Database on OF iPh, no go.
Re-set Sync details on OF Mac, no go.
Removed, restarted, reloaded, set sync, no go.
Removed, restarted, reloaded, restarted, set sync, good to go.