Hi Franceso,

hard to tell what goes wrong. If you use IE make sure Compatibility Mode is turned off. You might also consider to use no
Web-Proxy server for further tests. SOM 10.20 uses HTTPS (on Port 443) per default, but you should get re-directed when just using HTTP in the URL. I assume you don't have firewall running ?
You can open a command prompt as Administrator on the SOM Server and run the command
netstat -ano |findstr /c:":443 "
in the 2nd left column representing your local addresses you should see 0.0.0.0:443  and last column represents the Process ID (PID).
Run
tasklist | findstr <your_PID>
Check from the output of the two commands if you do have the system listening on port 443 (frist command) and if
ovjboss is the process behind (2nd command)

Here an example from my SOM system:
C:\>netstat -ano |findstr /c:":443 "
  TCP    0.0.0.0:443            0.0.0.0:0              LISTENING       9300
  TCP    15.226.162.80:63363    15.233.44.24:443       SYN_SENT        1204
  TCP    [::]:443               [::]:0                 LISTENING       9300
C:\>tasklist |findstr 9300
ovjboss.exe                   9300 Services                   0  4,729,988 K

Hello Dieter,

thanks for you answer. I confirm there is no proxy and IE11 compatibility mode i turned off. Following the output of netstat and tasklist commands:

C:\Windows\system32>netstat -ano |findstr /c:":443 "
  TCP    0.0.0.0:443            0.0.0.0:0              LISTENING       3268
  TCP    [::]:443               [::]:0                 LISTENING       3268
  TCP    [fe80::dc20:e935:f753:ce59]:443  [fe80::dc20:e935:f753:ce59]:5070
7  TIME_WAIT       0
  TCP    [fe80::dc20:e935:f753:ce59]:443  [fe80::dc20:e935:f753:ce59]:5070
8  TIME_WAIT       0

C:\Windows\system32>tasklist | findstr 3268
ovjboss.exe                   3268 Services                   0  6.388.572 K

C:\Windows\system32>

Francesco,
even though only in 'Time  Wait' state .. what is the process behind PID 5070 since your IPv6  address shows a different process id.

Dieter

Dieter,

I submitted again the netstat and tsklist commands. Following the output.

C:\Windows\system32>netstat -ano |findstr /c:":443 "
  TCP    0.0.0.0:443            0.0.0.0:0              LISTENING       3268
  TCP    [::]:443               [::]:0                 LISTENING       3268

C:\Windows\system32>tasklist | findstr 5070

C:\Windows\system32>tasklist | findstr 3268
ovjboss.exe                   3268 Services                   0  6.389.020 K

C:\Windows\system32>

Dieter,

I submitted again the netstat and tsklist commands. Following the output.

C:\Windows\system32>netstat -ano |findstr /c:":443 "
  TCP    0.0.0.0:443            0.0.0.0:0              LISTENING       3268
  TCP    [::]:443               [::]:0                 LISTENING       3268

C:\Windows\system32>tasklist | findstr 5070

C:\Windows\system32>tasklist | findstr 3268
ovjboss.exe                   3268 Services                   0  6.389.020 K

C:\Windows\system32>

Francesco,
difficult to say what might go wrong.  Your VMhost has sufficient memory ? We are also sure no other Web Service is running on the host ? (ok you netstat ouputs somehow confirm this). I recommend to raise a support case and provide the SOM Server logs.
(%OVINSTALLDIR%\bin\somgathersupportinfo.ovpl)

Dieter

Dieter,

thanks for you support. I raised a Service request and thi is the official answer from SOM/SE support team:

Hello Francesco

My name is xxxxxx from SOM/SE support team and I will assist you with case # yyyyyyyy > SOM 10.20 on VMware ESXi 6.5 won't start after installation

 The issue you have is because of your ESXi version. We do support ESX up to 6.0 in SOM 10.20.

I do believe we will have support for your version of ESXi in the next releases of SOM, unfortunately we do not have any ETA time for this release. 

Apologize for the inconvenience.

Francesco,
ok - even though I wonder, if that is really related to the ESXi Version. Unfortunately I don't have a ESXi 6.5 version available to do some tests. At the point when SOM 10.20 was released, there was no ESXi 6.5 version, that is why it hasn't been qualified.
I basically do not see a reason why the underneath ESXi Version should make the product not work (whereas I'm not a VMware Guru).

Dieter

Francesco,
ok - even though I wonder, if that is really related to the ESXi Version. Unfortunately I don't have a ESXi 6.5 version available to do some tests. At the point when SOM 10.20 was released, there was no ESXi 6.5 version, that is why it hasn't been qualified.
I basically do not see a reason why the underneath ESXi Version should make the product not work (whereas I'm not a VMware Guru).

Dieter