Connection timed out error occurs due to overloaded server or if server is not properly configured, or when our request is too heavy that server cannot handle.
How to remove error:
1. Deactivate all plugins and activate it one by one to find the problematic plugin.
2. If problem is in theme than deactivate the current theme and use default theme.
3. You can also increase your PHP memory limit using the wp-config.php file.Add the below code to it:
If you have shared hosting than you have limited access to increase the memory limit, i.e only certain amount of memory can be increased.
4. You can also increase maximum execution time in your php.ini file.
5. If all above fail try contacting your web hosts.