Which all config you made ?
If you are able to access GUI you must have configured the Webadmin ...It would be very important to understand that which all interfaced have been configured.
CHeck ipv4 a , ipv4 mmp , ipv4 b.
Try to access the MMP IP on port 22 ssh.
Still if you see some challenge look after the network firewall if any port is blocked b/w your PC & CMS server IP.
Certificates first needs to be generated by cli in SSH using below commands :
pki selfsigned name of cert
pki csr with the details of CN, subject alternatives names.
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What is the version of your CMS ?
Follow this Section 7.2.1 SSH login Page 36
If this on VM, please go to ESXi , take consol & enter the command which been shared above.
Solved! software version problem..We download and install new version of cms. 2.5.1 is the factory installed version and downloaded 2.6/2.8.