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Fixed in 2020.1.X

Fixed in 2018.4.X, 2019.3.X



Found in










Issue ID




UnityWebRequest fails to verify certificate when "Let's Encrypt Authority X1" certificate is present in system trust store



Reproduction steps:
1. Open Certificate Manager (In Windows, search for "Manage user certificates" in the Start menu)
2. If present, delete Let's Encrypt Authority X3 certificate under "Current User\Intermediate Certification Authorities\Certificates"
3. If not present, install the Let's Encrypt Authority X1 certificate attached below
4. Open the attached project (
5. Enter Play Mode

Expected result: WebRequest is successful and data is fetched
Actual result: The error "Curl error 51: Cert verify failed: UNITYTLS_X509VERIFY_FLAG_NOT_TRUSTED" is thrown and no data is fetched

Reproduced in: 2018.4.10f1, 2018.4.16f1, 2019.2.7f2, 2019.2.19f1, 2019.3.0b4, 2019.3.0f6, 2020.1.0a4
Not reproducible in: 2017.4.36f1, 2018.4.9f1, 2019.2.7f1, 2019.3.0b3, 2020.1.0a3, 2020.1.0a11, 2020.1.0a21

Regressed in: 2018.4.10f1, 2019.2.7f1, 2019.3.0b3, 2020.1.0a4, most likely caused by Case 1076758

  1. Resolution Note (fix version 2020.1):

    Fixed in 2020.1.0a11

  2. Resolution Note (fix version 2019.3):

    Fixed in 2019.3.3f1

  3. Resolution Note (fix version 2018.4):

    Fixed in 2018.4.18f1

Comments (47)

  1. t2_dasein

    May 08, 2020 12:30

    Curl error 51: Cert verify failed: UNITYTLS_X509VERIFY_FLAG_EXPIRED

    sorry it was this that i got actually

  2. t2_dasein

    May 08, 2020 12:28

    Just got this issue. Never had before.

  3. ilanmanor

    May 08, 2020 12:26

    it happened now and I cant playtest my game anymore 2019.3.06

  4. Ulyssius

    May 08, 2020 12:25

    + 1. Just got it in 2018.4.19f2 .

  5. WindOfWar

    May 08, 2020 12:25

    Same problem 2019.3.0f6. Never had it before today

  6. xpander

    May 08, 2020 12:22

    2018.4.14f1 Started to appear in Editor just today. We didn't see this error before.

  7. NWHCoding

    May 08, 2020 12:13

    Just got it in 2018.4.19f1 so not fixed.

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