I tried to login to the vCenter via ssh. As you can see there are no sign of smtp or gmail in /var/log
$ ssh root@10.1.1.2
VMware vCenter Server Appliance 6.7.0.40000
Type: vCenter Server with an embedded Platform Services Controller
root@10.1.1.2's password:
Warning: untrusted X11 forwarding setup failed: xauth key data not generated
Last login: Sat May 16 20:00:52 2020 from 10.1.1.1
Connected to service
* List APIs: "help api list"
* List Plugins: "help pi list"
* Launch BASH: "shell"
Command> shell
Shell access is granted to root
root@10 [ ~ ]# cd /var/log
root@10 [ /var/log ]# grep -ri smtp .
Binary file ./journal/36ab8ece4c2f4e359fba9c3a9481c82a/system@28829f1b349643cda72b81fe09807a39-0000000000698e51-0005a337c8a02994.journal matches
Binary file ./journal/36ab8ece4c2f4e359fba9c3a9481c82a/system.journal matches
Binary file ./journal/36ab8ece4c2f4e359fba9c3a9481c82a/system@28829f1b349643cda72b81fe09807a39-0000000000722d92-0005a4b3af155426.journal matches
root@10 [ /var/log ]# grep -ri gmail .
Binary file ./journal/36ab8ece4c2f4e359fba9c3a9481c82a/system.journal matches
root@10 [ /var/log ]#
Where are the detailed logs then?