Resolved Can't use Git package URLs with Unity 2019.4.1f1: "unable to verify the first certificate"

My project's manifest.json includes references to several UPM packages as Git repo URLs. However, Unity can't seem to download these packages. In fact, I can't seem to update my list of available packages.

These are the relevant error messages from the console. I get them whenever I try to refresh the available package list.

Code (csharp):

1. Cannot perform upm operation: unable to verify the first certificate [NotFound]
2. UnityEditor.EditorApplication:Internal_CallUpdateFunctions() (at /home/builduser/buildslave/unity/build/Editor/Mono/EditorApplication.cs:310)
3. Error searching for packages offline.
4. UnityEditor.EditorApplication:Internal_CallUpdateFunctions() (at /home/builduser/buildslave/unity/build/Editor/Mono/EditorApplication.cs:310)
5. [PackageManager] Error unable to verify the first certificate
6. UnityEditor.EditorApplication:Internal_CallUpdateFunctions() (at /home/builduser/buildslave/unity/build/Editor/Mono/EditorApplication.cs:310)

I'm using Unity 2019.4.1f1 on Ubuntu 20.04, on my home Wi-fi network. This happens with and without a VPN. Here's my manifest.json:

Code (csharp):

1. {
2.   "scopedRegistries": [
3.     {
4.       "name": "NPM",
5.       "url": "https://registry.npmjs.org",
6.       "scopes": [
7.         "clever-crow",
8.         "com.adlucem",
9.         "com.coffee",
10.         "com.digitalruby",
11.         "com.fluid",
12.         "com.iptech",
13.         "com.stansassets",
14.         "com.mambojambostudios.marvelous",
15.         "com.mambojambostudios.unity-atoms-base-atoms",
16.         "com.mambojambostudios.unity-atoms-fsm",
17.         "com.mambojambostudios.unity-atoms-core",
18.         "com.mambojambostudios.unity-atoms-mobile",
19.         "com.mambojambostudios.unity-atoms-mono-hooks",
20.         "com.mambojambostudios.unity-atoms-scene-mgmt",
21.         "com.mambojambostudios.unity-atoms-tags",
22.         "com.mambojambostudios.unity-atoms-ui",
23.         "com.oshoham",
24.         "com.unityfx",
25.         "io.extendreality",
26.         "jp.keijiro",
27.         "xyz.candycoded"
28.       ]
29.     },
30.     {
31.       "name": "Unofficial Unity Package Manager Registry",
32.       "url": "https://upm-packages.dev",
33.       "scopes": [
34.         "dev.monry.upm"
35.       ]
36.     },
37.     {
38.       "name": "XCrew",
39.       "url": "https://xcrew.dev",
40.       "scopes": [
41.         "com.xcrew"
42.       ]
43.     },
44.     {
45.       "name": "Unity NuGet Registry",
46.       "url": "https://unitynuget-registry.azurewebsites.net",
47.       "scopes": [
48.         "org.nuget"
49.       ]
50.     },
51.     {
52.       "name": "package.openupm.com",
53.       "url": "https://package.openupm.com",
54.       "scopes": [
55.         "ch.sttz.trimmer",
56.         "com.bgtools.playerpreferenceseditor",
57.         "com.coffee.ui-effect",
58.         "com.coffee.upm-git-extension",
59.         "com.johannesmp.unityscenereference",
60.         "com.johnsoncodehk.unity-asset-inspector",
61.         "com.littlebigfun.addressable-importer",
62.         "com.merlin.easyeventeditor",
63.         "com.openupm",
64.         "com.rfadeev.unityforge.propertydrawers",
65.         "com.starikcetin.quickplaytool",
66.         "com.supyrb.configurableshaders",
67.         "com.unity.project-auditor",
68.         "com.unity.uiextensions",
69.         "com.yasirkula.inspectplus",
70.         "dev.bullrich.asmdef-debug",
71.         "net.tnrd.histogrammer",
72.         "uni-git",
73.         "upm-embed"
74.       ]
75.     }
76.   ],
77.   "dependencies": {
78.     "ch.sttz.trimmer": "1.1.0",
79.     "com.baba-s.uni-active-tilemap-auto-changer": "https://github.com/baba-s/UniActiveTilemapAutoChanger.git",
80.     "com.baba-s.uni-application-path-window": "https://github.com/baba-s/UniApplicationPathWindow.git",
81.     "com.baba-s.uni-collapse-hierarchy-and-project-window": "https://github.com/baba-s/UniCollapseHierarchyAndProjectWindow.git",
82.     "com.baba-s.uni-deconstruction": "https://github.com/baba-s/UniDeconstruction.git",
83.     "com.baba-s.uni-reload-assemblies-locker": "https://github.com/baba-s/UniReloadAssembliesLocker.git",
84.     "com.bgtools.playerpreferenceseditor": "1.0.0",
85.     "com.coffee.ui-effect": "4.0.0-preview.9",
86.     "com.fluid.behavior-tree": "2.2.2",
87.     "com.fluid.simple-singleton": "1.0.0",
88.     "com.johannesmp.unityscenereference": "1.1.0",
89.     "com.johnsoncodehk.unity-asset-inspector": "1.0.0",
90.     "com.mambojambostudios.unity-atoms-core": "4.2.0",
91.     "com.mambojambostudios.unity-atoms-fsm": "4.2.0",
92.     "com.mambojambostudios.unity-atoms-mobile": "4.2.0",
93.     "com.mambojambostudios.unity-atoms-mono-hooks": "4.2.0",
94.     "com.mambojambostudios.unity-atoms-scene-mgmt": "4.2.0",
95.     "com.mambojambostudios.unity-atoms-tags": "4.2.0",
96.     "com.mambojambostudios.unity-atoms-ui": "4.2.0",
97.     "com.merlin.easyeventeditor": "1.0.3",
98.     "com.rfadeev.unityforge.propertydrawers": "1.0.0",
99.     "com.supyrb.configurableshaders": "0.7.1",
100.     "com.unity.2d.pixel-perfect": "2.0.4",
101.     "com.unity.2d.sprite": "1.0.0",
102.     "com.unity.2d.tilemap": "1.0.0",
103.     "com.unity.analytics": "3.4.0",
104.     "com.unity.assetbundlebrowser": "1.7.0",
105.     "com.unity.burst": "1.3.2",
106.     "com.unity.cloud.userreporting": "0.2.4-preview",
107.     "com.unity.collections": "0.9.0-preview.6",
108.     "com.unity.device-simulator": "2.2.2-preview",
109.     "com.unity.editorcoroutines": "1.0.0",
110.     "com.unity.editoriterationprofiler": "https://github.com/Unity-Technologies/com.unity.editoriterationprofiler.git",
111.     "com.unity.ext.nunit": "1.0.0",
112.     "com.unity.ide.rider": "2.0.5",
113.     "com.unity.jobs": "0.2.10-preview.12",
114.     "com.unity.mathematics": "1.1.0",
115.     "com.unity.memoryprofiler": "0.2.4-preview.1",
116.     "com.unity.mobile.android-logcat": "1.2.0-preview",
117.     "com.unity.performance-tracking": "https://github.com/Unity-Technologies/com.unity.performance-tracking.git",
118.     "com.unity.performance.profile-analyzer": "1.0.0",
119.     "com.unity.playablegraph-visualizer": "0.2.1-preview.3",
120.     "com.unity.postprocessing": "2.3.0",
121.     "com.unity.project-auditor": "0.2.1-preview",
122.     "com.unity.quicksearch": "2.0.0",
123.     "com.unity.recorder": "2.2.0-preview.4",
124.     "com.unity.settings-manager": "1.0.2",
125.     "com.unity.test-framework": "1.1.14",
126.     "com.unity.test-framework.performance": "2.2.0-preview",
127.     "com.unity.testtools.codecoverage": "0.3.0-preview",
128.     "com.unity.textmeshpro": "2.1.0-preview.14",
129.     "com.unity.timeline": "1.5.0-preview.2",
130.     "com.unity.ugui": "1.0.0",
131.     "com.unity.uiextensions": "2.1.0",
132.     "com.unity.vectorgraphics": "2.0.0-preview.12",
133.     "net.tnrd.histogrammer": "1.0.0",
134.     "upm-embed": "0.1.0",
135.     "xyz.candycoded.gitstatus": "2.1.0",
136.     "com.unity.modules.androidjni": "1.0.0",
137.     "com.unity.modules.animation": "1.0.0",
138.     "com.unity.modules.assetbundle": "1.0.0",
139.     "com.unity.modules.audio": "1.0.0",
140.     "com.unity.modules.director": "1.0.0",
141.     "com.unity.modules.imageconversion": "1.0.0",
142.     "com.unity.modules.imgui": "1.0.0",
143.     "com.unity.modules.jsonserialize": "1.0.0",
144.     "com.unity.modules.particlesystem": "1.0.0",
145.     "com.unity.modules.physics": "1.0.0",
146.     "com.unity.modules.physics2d": "1.0.0",
147.     "com.unity.modules.screencapture": "1.0.0",
148.     "com.unity.modules.tilemap": "1.0.0",
149.     "com.unity.modules.ui": "1.0.0",
150.     "com.unity.modules.uielements": "1.0.0",
151.     "com.unity.modules.unityanalytics": "1.0.0",
152.     "com.unity.modules.unitywebrequest": "1.0.0",
153.     "com.unity.modules.unitywebrequestassetbundle": "1.0.0",
154.     "com.unity.modules.unitywebrequestaudio": "1.0.0",
155.     "com.unity.modules.unitywebrequestwww": "1.0.0",
156.     "com.unity.modules.vr": "1.0.0",
157.     "com.unity.modules.xr": "1.0.0"
158.   }
159. }

 

It turns out that the XCrew registry's certificate had expired. Since I wasn't actually using any packages from it, I just removed it. Problem solved, case closed.