I am encountering a similar issue from Unity version 2019.4.30f1 and onwards.
My CI Platform is CircleCI and I am using game.ci docker images (based on Ubuntu 18.04). I have unity pro license.

The docker image tags with the Unity version 2019.4.21, 2019.4.22, 2019.4.29 worked fine for my existing project. I am seeing a difference in the log when I try to run exact same command for newer versions (2019.4.30 and onwards, including 2020.3.21). I found a key difference, which seems to be, unity 2019.4.30 and onwards can not detect my license to be "Pro" (in log it appears to be Pro License: NO). I am sharing log for the following command to release a seat example:

unity-editor -username "${UNITY_USERNAME}" -password "${UNITY_PASSWORD}" -serial "${UNITY_SERIAL}" -batchmode -nographics -returnlicense -quit || echo "Seat is free."

On Unity 2019.4.29, the output for the command looks like this

'[LicensingClient] ERROR Failed to connect to local IPC
[Licensing::Module] Failed to connect to channel: LicenseClient-root
[Licensing::Module] Successfully launched the LicensingClient
[SignatureVerifier] Application signature verification not supported on this platform.
[Licensing::Module] Successfully connected to LicensingClient on channel: LicenseClient-root
[Licensing::Module] Successfully launched and connected to LicensingClient
Entitlement-based licensing initiated
[LicensingClient] Licenses Updated successfully in LicensingClient

LICENSE SYSTEM [20211116 13:4:25] Failed to return license: Unity license has not been activated, and cannot be returned.
Seat is free.
CircleCI received exit code 0'

The same command on 2019.4.30 would produce the following log.

'Unity Editor version: 2019.4.30f1 (e8c891080a1f)
Branch: 2019.4/*******
Build type: Debug
Batch mode: YES
System name: Linux
Distro version: #117-Ubuntu SMP Mon Aug 2 21:43:04 UTC 2021
Kernel version: 4.15.0-1110-aws
Architecture: x86_64
Available memory: 70340 MB
[LicensingClient] ERROR Failed to connect to local IPC
[Licensing::Module] Failed to connect to channel: LicenseClient-root
[Licensing::Module] Successfully launched the LicensingClient
[SignatureVerifier] Application signature verification not supported on this platform.
[Licensing::Module] Successfully connected to LicensingClient on channel: LicenseClient-root
[Licensing::Module] Successfully launched and connected to LicensingClient
Entitlement-based licensing initiated
[LicensingClient] Licenses Updated successfully in LicensingClient
[Licensing::Module] License is not active (com. unity. editor .headless). HasEntitlements will fail.
Pro License: NO

LICENSE SYSTEM [20211116 12:57:26] Failed to return license: Unity license has not been activated, and cannot be returned.
Checking for leaked weakptr:
Found no leaked weakptrs.
##utp:{"type":"MemoryLeaks","version":2,"phase":"Immediate","time":1637067446176,"processId":246,"allocatedMemory":73206,"memoryLabels":[{"Default":-552},{"Manager":680},{"Serialization":40},{"BaseObject":12296},{"String":14012},{"DynamicArray":86},{"Curl":1112},{"PoolAlloc":120},{"GI":3064},{"VR":80},{"RestService":256},{"License":264},{"UnityConnect":21160},{"Collab":57},{"LocalIPC":99},{"ProfilerEditor":19880},{"Licensing":552}]}
Seat is free.
CircleCI received exit code 0'

Similarly, the following android build command works perfectly fine with 2019.4.29.
unity-editor -username "${UNITY_USERNAME}" -password "${UNITY_PASSWORD}" -serial "${UNITY_SERIAL}" -batchmode -nographics -accept-apiupdate -buildTarget Android -executeMethod Voodoo.CI.BuildAndroid.Build

but when it comes to 2019.4.30 and onwards, the build fails due to missing a valid license. Although It seems to gets activated as expected. The log would look like this.

'Unity Editor version: 2019.4.30f1 (e8c891080a1f)
Branch: 2019.4/*******
Build type: Debug
Batch mode: YES
System name: Linux
Distro version: #117-Ubuntu SMP Mon Aug 2 21:43:04 UTC 2021
Kernel version: 4.15.0-1110-aws
Architecture: x86_64
Available memory: 70340 MB
[LicensingClient] ERROR Failed to connect to local IPC
[Licensing::Module] Failed to connect to channel: LicenseClient-root
[Licensing::Module] Successfully launched the LicensingClient
[SignatureVerifier] Application signature verification not supported on this platform.
[Licensing::Module] Successfully connected to LicensingClient on channel: LicenseClient-root
[Licensing::Module] Successfully launched and connected to LicensingClient
Entitlement-based licensing initiated
[LicensingClient] Licenses Updated successfully in LicensingClient
[Licensing::Module] License is not active (com.unity.editor.headless). HasEntitlements will fail.
Pro License: NO
DisplayProgressbar: Unity license
[1116/125727:ERROR:browser_main_loop.cc(161)] Running without the SUID sandbox! See xxxxx
xcode.google.com/p/chromium/wiki/LinuxSUIDSandboxDevelopment for more information on developing with the sandbox on.
[1116/125727:ERROR:sandbox_linux.cc(308)] InitializeSandbox() called with multiple threads in process gpu-process
[UnityConnectServicesConfig] config is NOT valid, switching to *******
User ******************* logged in successfully

LICENSE SYSTEM [20211116 12:57:32] Starting license activation with account *******************

LICENSE SYSTEM [20211116 12:57:32] Opening xxxxxxlicense.unity3d.com/update/poll?cmd=9&tx_id=62c6bd40d972c8bc1ab8c9c3e1a19a00&(serial removed)

LICENSE SYSTEM [20211116 12:57:32] Posting <?xml version="1.0" encoding="UTF-8"?><root><SystemInfo><IsoCode>C.UTF</IsoCode><UserName>(unset)</UserName><OperatingSystem>Linux 4.15 Ubuntu 18.04 64bit</OperatingSystem><OperatingSystemNumeric>415</OperatingSystemNumeric><ProcessorType>Intel(R) Xeon(R) Platinum 8124M CPU @ 3.00GHz</ProcessorType><ProcessorSpeed>3400</ProcessorSpeed><ProcessorCount>36</ProcessorCount><ProcessorCores>36</ProcessorCores><PhysicalMemoryMB>70340</PhysicalMemoryMB><ComputerName>b43979efe61d</ComputerName><ComputerModel>PC</ComputerModel><UnityVersion>2019.4.30f1</UnityVersion><SupportedLicenseVersion>6.x</SupportedLicenseVersion></SystemInfo><License id="Terms"><MachineID Value="D7nTUnjNAmtsUMcnoyrqkgIbYdM=" /><MachineBindings><Binding Key="1" Value="576562626572264761624c65526f7578" /><Binding Key="2" Value="576562626572264761624c65526f7578" /></MachineBindings><UnityVersion Value="2019.4.30f1" /></License></root>

LICENSE SYSTEM [20211116 12:57:33] Received xxxxxxxxxlicense.unity3d.com/update/poll?cmd=9&tx_id=62c6bd40d972c8bc1ab8c9c3e1a19a00&(serial removed)

LICENSE SYSTEM [20211116 12:57:33] Headers:
HTTP/1.1 200 OK
X-RX: GEN-f2384761-e2f7-4257-9956-27ae0ba3f682
sc-request-id: e6a6df48-d1d1-4192-90d8-340a7fb8f0ac
sc-token-expires-in: 7245
Cache-Control: no-cache, no-store, must-revalidate
Pragma: no-cache
Expires: 0
Vary: Accept-Encoding
Content-Encoding: deflate
Content-Type: text/plain
Content-Length: 161

LICENSE SYSTEM [20211116 12:57:33] Opening xxxxxxxxactivation.unity3d.com/license.fcgi?CMD=9&TX=62c6bd40d972c8bc1ab8c9c3e1a19a00&RX=GEN-f2384761-e2f7-4257-9956-27ae0ba3f682

LICENSE SYSTEM [20211116 12:57:33] Posting <?xml version="1.0" encoding="UTF-8"?><root><SystemInfo><IsoCode>C.UTF</IsoCode><UserName>(unset)</UserName><OperatingSystem>Linux 4.15 Ubuntu 18.04 64bit</OperatingSystem><OperatingSystemNumeric>415</OperatingSystemNumeric><ProcessorType>Intel(R) Xeon(R) Platinum 8124M CPU @ 3.00GHz</ProcessorType><ProcessorSpeed>3400</ProcessorSpeed><ProcessorCount>36</ProcessorCount><ProcessorCores>36</ProcessorCores><PhysicalMemoryMB>70340</PhysicalMemoryMB><ComputerName>b43979efe61d</ComputerName><ComputerModel>PC</ComputerModel><UnityVersion>2019.4.30f1</UnityVersion><SupportedLicenseVersion>6.x</SupportedLicenseVersion></SystemInfo><License id="Terms"><MachineID Value="D7nTUnjNAmtsUMcnoyrqkgIbYdM=" /><MachineBindings><Binding Key="1" Value="576562626572264761624c65526f7578" /><Binding Key="2" Value="576562626572264761624c65526f7578" /></MachineBindings><UnityVersion Value="2019.4.30f1" /></License></root>

LICENSE SYSTEM [20211116 12:57:34] Received xxxxxxactivation.unity3d.com/license.fcgi?CMD=9&TX=62c6bd40d972c8bc1ab8c9c3e1a19a00&RX=xxxxxxxxxxxxxxxx

LICENSE SYSTEM [20211116 12:57:34] Headers:
HTTP/1.1 200 OK
sc-request-id: xxx
Vary: Accept-Encoding
Content-Encoding: deflate
sc-token-expires-in: 7244
Cache-Control: no-cache, no-store, must-revalidate
Pragma: no-cache
Expires: 0
Content-Type: text/xml
Content-Length: 1136

LICENSE SYSTEM [20211116 12:57:34] License activated successfully with user: *******************

LICENSE SYSTEM [20211116 12:57:34] Next license update check is after 2021-11-17T12:57:33

[LicensingClient] Licenses Updated successfully in LicensingClient
No valid Unity Editor license found. Please activate your license.
Checking for leaked weakptr:
Found no leaked weakptrs.
##utp:{"type":"MemoryLeaks","version":2,"phase":"Immediate","time":1637067494366,"processId":319,"allocatedMemory":119339,"memoryLabels":[{"Default":-456},{"Manager":800},{"Serialization":40},{"BaseObject":12296},{"String":14465},{"DynamicArray":214},{"Curl":1112},{"PoolAlloc":120},{"GI":3064},{"VR":80},{"Secure":41592},{"EditorUtility":3480},{"RestService":256},{"License":264},{"UnityConnect":21320},{"Collab":57},{"LocalIPC":99},{"ProfilerEditor":19880},{"Licensing":656}]}
CircleCI received exit code 0'

It's clearly an issue with either Unity Hub or Unity 2019.4.30 and onwards. Really looking forward to a solution from Unity side.

patientfusion.us

We were using containers successfully until 2019.3. We only just upgraded to 2019.3

+1

This is blocking an upgrade to Unity 2019.3 in Ubuntu containers as well.

Looks like we can't upgrade to 2019.3 or 2020.1 either.
At least this issue was reopened after being marked as "won't fix" at first.

If this is not fixed it will prevent us from upgrading to 2019.3.

How is "won't fix" acceptable for this issue?

There's no explanation as to why, nor any workarounds. There's a lot of people using this to automate their Unity builds, this is clearly not acceptable.

I feel like you guys are actively making sure automating our builds is a pain to sell your Unity cloud build.

Seems like the check is just done the wrong way around, since INetworkListManager::GetConnectivity is obviously not an authoritative source of knowledge in practice. The right way would be to attempt to connect to the service first, and to perform a general Internet connectivity check on the network interface as an additional diagnostic if it fails.

Running Unity in a Docker container is a common pattern for building CI, so this is going to present a major blocker to updating for many people. In our case, releases up to 2019.1 are working well, but with 2019.3 betas we've started to run into trouble.