KB: Troubleshoot "Error from portal365.altium.com"

Solution Details

Here are things to try:

1.) PORTS AND ADRESSES

Please have your IT support check that the addresses and ports indicated in this Knowledge Base article are open in your network:
https://www.altium.com/documentation/knowledge-base/altium-designer/cannot-install-or-use-altium-possibly-due-to-url-and-ports-being-blocked 

2,) VIRUS PROTECTION AND FIREWALL SETTINGS

Have your IT Support check if antivirus/firewall applications could be stopping necessary network traffic.

3.) OFFLINE INSTALLER

Please do a fresh reinstallation with the offline installer:
https://www.altium.com/documentation/knowledge-base/altium-designer/offline-installer

4.) TRANSPORT LAYER SECURITY



Please confirm that TLS 1.2 is enabled in your system using the following procedure:

Press "Win+I" to launch the Windows Settings panel
Type "Internet Options" in the search bar
Launch the Internet Properties panel (Figure 1)
Click on the Advanced tab
Scroll down to the bottom of the list to find the "Security" section
Confirm "Use TLS 1.2" is enabled (Figure 2)



5.) FOR THIS ERROR



If the issue is reproducible at the same time on a different PC in the same network, look into corporate firewall/router, antivirus, proxy etc. (see #1 above)

If it is local to only one PC, look into local antivirus, DNS, proxy cache etc.  (see #2 above) Try to open the URL mentioned in the error (https://portal365.altium.com) in Internet Explorer (or Edge) as Altium Designer and Internet Explorer uses the same functions to access web sites.  You should see an OK message. Check if the certificate is OK and valid by clicking on lock icon next to URL, select 'Connection is secure' to confirm it is issued by Amazon.