[proxy_fcgi:error] [pid 3659] (70007)The timeout specified has expired: [client :39524] AH01075: Error dispatching request to : (polling)

Problem:
[proxy_fcgi:error] [pid 3659] (70007)The timeout specified has expired: [client :39524] AH01075: Error dispatching request to : (polling)

Solution:
vim /etc/httpd/conf/httpd.conf
Timeout 600

systemctl reload httpd

Reference: https://stackoverflow.com/questions/46594731/php-apache-error-dispatching-request

Failed to connect to ssh after recovering an ec2 snapshot

Solution 1
1. Use verbose mode to see the error

ssh -v xxx.xxx.xxx.xxx

2. Delete the corresponding row in ~/.ssh/known_hosts

Reference: https://stackoverflow.com/questions/18551556/permission-denied-publickey-when-ssh-access-to-amazon-ec2-instance

Solution 2
1. Detach the volume
2. Create a temporary ec2 instance and attach the volume into it
3. Login to the temporary ec2 instance
4. Check the device code

lsblk

5. Mount the volume (/dev/xvdg)

mkdir mount_point
mount /dev/xvdg1 mount_point

6. Change the ssh config.
7. Attach the volume back to the original ec2 instance
8. Delete the temporary ec2 instance
9. Delete the corresponding row in ~/.ssh/known_hosts and try again

Reference:
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/TroubleshootingInstancesConnecting.html#TroubleshootingInstancesConnectingMindTerm