Change smtp port to send emails notification from vCenter not working

Hello vmware community !

We have 3 vCenter (with 3 essential license) and I'm trying to send notification via vCenter using gmail account (with TLS autentication).

I changed in Advance setting, the smtp port from 25 to 587, But I still see the traffic on my firewall through port 25....

I tryied to restart the vCenter, but the traffic still on port 25.... What I have to do to make the port changes take effect? please community, can any one help me? thanks in advance!

I'm ussing the last version on ESXi and vCenter (v.6.5.0.5500)

this is the general setting:

And this is the advance settings:

And this is the traffic on my firewall:

many thanks of all !!