Wifi: can't connect to work wifi Galaxy Note 7

[BSTL]

When I select my work wifi, it directs me to sign in.  Upon selecting to sign in, I get the following message:

'SSL certificate not trusted'

'The security certificate for this network is not from a trusted authority.  We do not recommend that you connect to this network.'

Then, when selecting 'connect', I get the following message:  The webpage at http://connectivitycheck.gstatic.com/generate_204 could not be loaded because:

net::ERR_EMPTY_RESPONSE/

My phone work on all other wifi, this is the only one that I've had difficulty with.

Thanks