When working with HTTPS connections in Linux environments, you might encounter the frustrating "Issued certificate not yet valid" error. This typically occurs when:

• The server's SSL certificate has a future start date
• Your system clock is out of sync
• There's a timezone mismatch between client and server

For temporary workarounds with wget, you have these options:

# Skip certificate validation (not recommended for production)
wget --no-check-certificate https://example.com/file.zip

# Alternative using curl
curl -k https://example.com/file.zip -o file.zip

Instead of disabling certificate checks, consider these proper fixes:

1. Verify and Correct System Time

# Check current system time
date

# Sync time using NTP (requires root)
sudo apt install ntpdate
sudo ntpdate pool.ntp.org

2. Check Certificate Details

# View certificate validity period
openssl s_client -connect example.com:443 2>/dev/null | openssl x509 -noout -dates

# Expected output:
# notBefore=Jun  1 00:00:00 2023 GMT
# notAfter=May 31 23:59:59 2024 GMT

3. Update CA Certificates

# On Debian/Ubuntu
sudo apt update && sudo apt install ca-certificates

# On CentOS/RHEL
sudo yum update ca-certificates

For deeper investigation, use OpenSSL's verbose mode:

openssl s_client -connect example.com:443 -servername example.com -showcerts

Look for the "Verify return code" in the output. Code 9 specifically indicates the "certificate not yet valid" error.

To prevent future time-related issues, set up automatic time synchronization:

# For systemd systems
sudo timedatectl set-ntp true

# Verify status
timedatectl status

If you've verified the certificate is genuinely invalid (not just a time issue), you should:

1. Contact the website administrator
2. Consider if this indicates a potential security issue
3. Document the exception if you must proceed with the connection

---

When working with secure connections, you might encounter the frustrating "Issued certificate not yet valid" error. This commonly occurs when:

• The server's SSL certificate start date is in the future
• Your local system clock is out of sync
• There's a timezone mismatch between client and server

wget https://www.example.com
--2023-12-20 10:00:00--  https://www.example.com/
ERROR: The certificate of 'www.example.com' is not yet valid.

For testing purposes, you can bypass the check (not recommended for production):

wget --no-check-certificate https://www.example.com

For OpenSSL testing:

openssl s_client -connect example.com:443 -servername example.com -showcerts \
| openssl x509 -noout -dates

1. Verify and correct your system time:

# Linux/macOS
date
sudo ntpdate pool.ntp.org

# Windows (admin command prompt)
w32tm /resync

2. Check certificate validity manually:

openssl s_client -connect example.com:443 2>/dev/null \
| openssl x509 -noout -text | grep -A 2 Validity

Sometimes the problem stems from timezone misconfiguration. Verify with:

timedatectl status  # On systemd systems
tzselect            # Interactive timezone selector

For scripts that need to handle potential certificate issues:

#!/bin/bash

URL="https://example.com"
CERT_CHECK=$(wget --spider --server-response "$URL" 2>&1 | grep "certificate")

if [[ $CERT_CHECK == *"not yet valid"* ]]; then
    echo "Warning: Certificate validity issue detected"
    # Add notification logic here
fi

If you control the server, verify the certificate installation:

# Check Apache configuration
apachectl -t -D DUMP_VHOSTS | grep -A 10 example.com

# For Nginx
nginx -T | grep -A 10 ssl_certificate