it seems the certificat validity is over.
same as The certificate for mail.ecloud.global expired on 2/3/2026 - #8 by Mordisquitos
Cannot confirm this issue:
$ openssl s_client mail.ecloud.global:993
CONNECTED(00000003)
depth=2 C = US, O = Internet Security Research Group, CN = ISRG Root X1
verify return:1
depth=1 C = US, O = Let's Encrypt, CN = R13
verify return:1
depth=0 CN = mail.ecloud.global
verify return:1
---
Certificate chain
0 s:CN = mail.ecloud.global
i:C = US, O = Let's Encrypt, CN = R13
a:PKEY: rsaEncryption, 2048 (bit); sigalg: RSA-SHA256
v:NotBefore: Jan 6 00:08:55 2026 GMT; NotAfter: Apr 6 00:08:54 2026 GMT
1 s:C = US, O = Let's Encrypt, CN = R13
i:C = US, O = Internet Security Research Group, CN = ISRG Root X1
a:PKEY: rsaEncryption, 2048 (bit); sigalg: RSA-SHA256
v:NotBefore: Mar 13 00:00:00 2024 GMT; NotAfter: Mar 12 23:59:59 2027 GMT
---
You refer the outgoing server using Port 25 or 587 and STARTTLS:
$ openssl s_client -connect mail.ecloud.global:25 -starttls smtp
CONNECTED(00000003)
depth=2 C = US, O = Internet Security Research Group, CN = ISRG Root X1
verify return:1
depth=1 C = US, O = Let's Encrypt, CN = R12
verify return:1
depth=0 CN = mail.ecloud.global
verify error:num=10:certificate has expired
notAfter=Feb 4 00:03:29 2026 GMT
verify return:1
depth=0 CN = mail.ecloud.global
notAfter=Feb 4 00:03:29 2026 GMT
verify return:1
---
Certificate chain
0 s:CN = mail.ecloud.global
i:C = US, O = Let's Encrypt, CN = R12
a:PKEY: rsaEncryption, 2048 (bit); sigalg: RSA-SHA256
v:NotBefore: Nov 6 00:03:30 2025 GMT; NotAfter: Feb 4 00:03:29 2026 GMT
1 s:C = US, O = Let's Encrypt, CN = R12
i:C = US, O = Internet Security Research Group, CN = ISRG Root X1
a:PKEY: rsaEncryption, 2048 (bit); sigalg: RSA-SHA256
v:NotBefore: Mar 13 00:00:00 2024 GMT; NotAfter: Mar 12 23:59:59 2027 GMT
.
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