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404.school SSL Certificate – Valid, expires 31 Dec 2026 | CubDomain

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404.school
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SSL certificate

4

404.schoolSSL certificate & chain

Status: Valid
Expires in: 55 days
Issuer: Let's Encrypt
Chain: 4 certificates

Chain1 · Site certificate404.school 2 · IntermediateYR1 3 · IntermediateRoot YR 4 · RootISRG Root X1

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Certificate chain

1 · Site certificateValid404.schoolIssued by YR1Expires 31 Dec 2026
2 · IntermediateValidYR1

Issued by Root YR

Expires 2 Sept 2028

→3 · IntermediateValidRoot YRIssued by ISRG Root X1Expires 2 Sept 2032

→4 · RootValidISRG Root X1Self-signed rootExpires 4 Jun 2035

Each certificate is shown in full below, from the site's own to the root.

1

Site certificate

404.school

Valid

Issued to

Common name (CN): 404.school

Issued by

Common name (CN): YR1
Organisation (O): Let's Encrypt
Country (C): US

Validity

Valid from: 2 Oct 2026, 15:10 UTC
Valid until: 31 Dec 2026, 15:10 UTC
Days remaining: 55

Technical details

Serial number: 05:72:3A:8E:50:E7:41:29:A7:CF:59:07:C8:2D:92:24:30:32
Signature algorithm: sha256RSA
Matches the domain: Yes

Names covered Subject Alternative Names · 2

404.school
www.404.school

2

Intermediate

YR1

Valid

Issued to

Common name (CN): YR1
Organisation (O): Let's Encrypt
Country (C): US

Issued by

Common name (CN): Root YR
Organisation (O): ISRG
Country (C): US

Validity

Valid from: 3 Sept 2025, 00:00 UTC
Valid until: 2 Sept 2028, 23:59 UTC
Days remaining: 666

Technical details

Serial number: 00:A2:02:53:F1:5F:26:91:C0:5D:C1:CE:13:B9:BC:CA:4E
Signature algorithm: sha256RSA

3

Intermediate

Root YR

Valid

Issued to

Common name (CN): Root YR
Organisation (O): ISRG
Country (C): US

Issued by

Common name (CN): ISRG Root X1
Organisation (O): Internet Security Research Group
Country (C): US

Validity

Valid from: 13 May 2026, 00:00 UTC
Valid until: 2 Sept 2032, 23:59 UTC
Days remaining: 2127

Technical details

Serial number: 00:F2:4B:6D:17:F9:D9:AD:7C:B1:C9:FE:A7:87:82:69:9F
Signature algorithm: sha256RSA

4

Root

ISRG Root X1

Valid

Issued to

Common name (CN): ISRG Root X1
Organisation (O): Internet Security Research Group
Country (C): US

Issued by

Common name (CN): Self-signed
Organisation (O): Internet Security Research Group
Country (C): US

Validity

Valid from: 4 Jun 2015, 11:04 UTC
Valid until: 4 Jun 2035, 11:04 UTC
Days remaining: 3131

Technical details

Serial number: 00:82:10:CF:B0:D2:40:E3:59:44:63:E0:BB:63:82:8B:00
Signature algorithm: sha256RSA

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