Keep getting that error even though I allowed UnityPackageManager and UnityEditor to connect through firewall. My Unity version is 2020.1.2f1 and here are da logs
upm-diag.txt
[2021-09-15T14:13:40.855Z][INFO] Opened report file 'C:\ProgramData\Unity\UnityPackageManagerDiagnostics\diagnostic_report_15_09_2021_171340,08.txt'
[2021-09-15T14:13:40.857Z][INFO] Starting diagnostics
[2021-09-15T14:13:40.859Z][INFO][UpmRegistryReachable] Sending HEAD request to https://packages.unity.com
[2021-09-15T14:13:41.484Z][INFO][PingUpmRegistry] Starting ping test on 'http://packages.unity.com/com.unity.package-manager.metadata'
[2021-09-15T14:13:46.750Z][INFO][PingUpmDownload] Starting ping test on 'http://download.packages.unity.com/com.unity.package-manager.metadata/-/com.unity.package-manager.metadata-0.0.1.tgz'
[2021-09-15T14:13:52.777Z][INFO][UpmRegistryDownloadSpeed] Starting speed test with UPM registry
[2021-09-15T14:14:03.294Z][INFO][UpmRegistryDownloadSpeed] Download: 18.42 Megabits per second
[2021-09-15T14:14:03.296Z][INFO][Speedtest.Net] Starting speed test with Speedtest.net
[2021-09-15T14:14:14.146Z][INFO][Speedtest.Net] Download: 34.66 Megabits per second
[2021-09-15T14:14:14.146Z][INFO][Speedtest.Net] Upload: 51.82 Megabits per second
[2021-09-15T14:14:14.156Z][INFO][UpmHealthCheck] Starting health check
[2021-09-15T14:14:14.165Z][ERROR][UpmHealthCheck] spawn UNKNOWN
[2021-09-15T14:14:14.168Z][INFO] Finished diagnostics
[2021-09-15T14:14:14.169Z][INFO] Created report at 'C:\ProgramData\Unity\UnityPackageManagerDiagnostics\diagnostic_report_15_09_2021_171340,08.txt'
diagnostic_report_15_09_2021_171340,08.txt
Unity Package Manager Diagnostics (v0.1.5)
============
Ran 7 checks
============
6 succeeded
1 did not run
============
✅ UPM registry reachable (PASS)
Make an HTTP request to the UPM package registry
>> HTTP/1.1 200 OK
>> X-Powered-By: Express
>> Provider: Genesis
>> Date: Wed, 15 Sep 2021 14:13:42 GMT
>> Connection: close
✅ Ping UPM registry (PASS)
Measure the latency of the UPM package registry API
>> 6 pings made in 5.211 seconds
>> Average latency: 138.73 ms
>> Minimum latency: 137.89 ms
>> Maximum latency: 139.87 ms
>> Standard deviation: 0.67
✅ Ping UPM download (PASS)
Measure the latency of the UPM package download endpoint
>> 6 pings made in 6.024 seconds
>> Average latency: 25.12 ms
>> Minimum latency: 24.67 ms
>> Maximum latency: 26.84 ms
>> Standard deviation: 0.85
✅ UPM registry download speed (PASS)
Test the Internet connection using the UPM package registry
>> Measured speed to the UPM registry: 18.42 Megabits per second
✅ Speedtest.net (PASS)
Test the Internet connection using Speedtest.net
>> Measured speed to the Speedtest.net server: 34.66 Megabits per second
✅ HTTP proxy environment variables (PASS)
Detect whether proxy-related environment variables are set (HTTP_PROXY, HTTPS_PROXY, ALL_PROXY, NO_PROXY, UNITY_PROXYSERVER, UNITY_NOPROXY)