Okay, lets start with some basic troubleshooting.
How is your website setup with AWS, do you use a load balancer or anything, or just the standard gateway.
Is the IP address of the server the same? Do you use elastic IP addresses to provide your public IP for your server? I ran a DIG command against your domain:
; <> DiG 9.9.4-RedHat-9.9.4-73.el7_6 <> A tingchihwang.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 13529
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;tingchihwang.com. IN A
;; ANSWER SECTION:
tingchihwang.com. 300 IN A 126.96.36.199
;; Query time: 69 msec
;; SERVER: 192.168.1.53#53(192.168.1.53)
;; WHEN: Sun Apr 28 15:52:59 MDT 2019
;; MSG SIZE rcvd: 61
It shows the IP for your A record is 188.8.131.52. Does this match what your server shows and what AWS shows as your public IP?
I ran a whois, and it shows you are using the DNS servers in Route 53 to manage those A records.
m-(~)-(5 files, 100Kb)--> whois tingchihwang.com
Domain Name: TINGCHIHWANG.COM
Registry Domain ID: 1901041615_DOMAIN_COM-VRSN
Registrar WHOIS Server: whois.godaddy.com
Registrar URL: http://www.godaddy.com
Updated Date: 2019-02-22T16:47:13Z
Creation Date: 2015-02-05T20:17:02Z
Registry Expiry Date: 2020-02-05T20:17:02Z
Registrar: GoDaddy.com, LLC
Registrar IANA ID: 146
Registrar Abuse Contact Email: firstname.lastname@example.org
Registrar Abuse Contact Phone: 480-624-2505
Domain Status: clientDeleteProhibited https://icann.org/epp#clientDeleteProhibited
Domain Status: clientRenewProhibited https://icann.org/epp#clientRenewProhibited
Domain Status: clientTransferProhibited https://icann.org/epp#clientTransferProhibited
Domain Status: clientUpdateProhibited https://icann.org/epp#clientUpdateProhibited
Name Server: NS-1361.AWSDNS-42.ORG
Name Server: NS-2007.AWSDNS-58.CO.UK
Name Server: NS-494.AWSDNS-61.COM
Name Server: NS-705.AWSDNS-24.NET
URL of the ICANN Whois Inaccuracy Complaint Form: https://www.icann.org/wicf/
If the IP changed for some reason, you can update your A record, however, if you don't have an elastic IP, I would get one, they are free as long as they are connected to an EC2 instance.
Another thing to try is rebooting the instance, see if that clears things out. If you STOP the instance completely and are not using an elastic IP, you will get a new IP address when you start it back up. So you'll want to update your A record at that time.
Are you getting any specific error messages? When I attempt to connect to the site it just times out.
Let me know if any of these things work out for you.