Cant't install offline extension

[FabienD]

Hi,

When I try to install an offline extension (Active directory, DNS, DHCP, ...), I receive the following error message.

Couldn't install the extension: 'DNS (Preview)'. Error: Failed to install package msft.sme.dns. Error: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel.

My server does have a "web-Server" certificate signed by my certification authority (recognized on the domain) and is accessible via https.

A way to solve this problem?

Thank you

[#2]

@FabienD 

 I too am failing to install Windows Admin Center extensions in an offline mode, but with a different error.

I've success fully copied all the .nupkg files to the "C:\temp" directory on the WAC server itself.

I've successfully registered the feed "C:\temp" and the .nupkg files do indeed show up in the "Available extensions" area.

However -- when you click "Install" it fails with:

ERROR:

Couldn't install the extension: 'Active Directory'. Error: Failed to install package msft.sme.active-directory. Error: Unable to connect to the remote server

I've tried making the "C:\temp" directory have "Everyone" = "Full" NTFS permissions. No change.

I've tried accessing the WAC console with FQDN/shortname/localhost and 127.0.0.1 in the URL field. Same error.

Tried rebooting the WAC server after registering the new "C:\temp" feed. Same error.

The puzzling piece is "unable to connect to the remote server" which doesn't make sense as it is connecting to itself.

[#3]

@pbergergeoblue  about the error: Unable to connect to the remote server i already opened a case to Microsoft.

what i can say is:

- even if WAC internet access is set to No access, it still goes to Internet.

- even if we open internet access to the whitelist URLs for WAC service

the following URLs are not enough

https://management.azure.com/

https://graph.microsoft.com

https://login.microsoftonline.com

https://pkgs.dev.azure.com/

https://aka.ms/sme-extension-feed

as it seems it goes to the following URLs as well

*. blob.core.windows.net

*. store.core.windows.net

anyway if you open the access to all  Microsoft Public IP address blocks  https://www.microsoft.com/en-us/download/details.aspx?id=53602 

it works...

I'm still waiting an official answer about the full/complete/right list of URLs to be whitelisted... if the server has no direct internet access...

[#4]

@Chris81 about your answer:

"anyway if you open the access to all  Microsoft Public IP address blocks  https://www.microsoft.com/en-us/download/details.aspx?id=53602 

it works..."

How can you exactly open these Microsoft Public IP address blocks?

Wish you a nice Day!