TLDR: Disable HTTP/2 on the server to prevent duplicate tickets.
Original discussion here.
Ticket create using REST API causes duplicate emails
Seems that this is caused by HTTP/2 and HTTP/1.1 request being sent to the server depending on the browser. You can clearly see this happening in the IIS logs as shown below:
2024-10-25 14:50:32 W3SVC1 bchdm5 10.104.0.15 POST /createticket-test/submit.py - 443 - 10.108.52.213 HTTP/2 Mozilla/5.0+(Windows+NT+10.0;+Win64;+x64)+AppleWebKit/537.36+(KHTML,+like+Gecko)+Chrome/130.0.0.0+Safari/537.36 - https://REDACTED/createticket-test/partsrec-art.html REDACTED 200 0 87 0 1143 6919
2024-10-25 14:50:39 W3SVC1 bchdm5 10.104.0.15 POST /createticket-test/submit.py - 443 - 10.108.52.213 HTTP/1.1 Mozilla/5.0+(Windows+NT+10.0;+Win64;+x64)+AppleWebKit/537.36+(KHTML,+like+Gecko)+Chrome/130.0.0.0+Safari/537.36 - https://REDACTED/createticket-test/partsrec-art.html REDACTED 200 0 0 1446 1130 7027
After disabling HTTP/2 in the registry using the following instructions:
- Start > Run and type regedit in the displayed box.
- Navigate to the folder/path: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\HTTP\Parameters
- Under the Parameters folder, right-click in the right side pane, select New > DWORD (32-bit) value. Specify the value name as EnableHttp2Tls and set its value data to 0 (zero).
- Repeat that to add another value named EnableHttp2Cleartext and its value data to 0.
- Restart the machine.
Upon rebooting the server, no more HTTP/2 request are being sent to the server thus no more duplicate tickets:
2024-10-25 15:24:25 W3SVC1 bchdm5 10.104.0.15 GET /createticket-test/partsrec-art.html - 443 - 10.104.0.15 HTTP/1.1 Mozilla/5.0+(Windows+NT+10.0;+Win64;+x64)+AppleWebKit/537.36+(KHTML,+like+Gecko)+Chrome/130.0.0.0+Safari/537.36 - - REDACTED 304 0 0 195 791 42
2024-10-25 15:24:28 W3SVC1 bchdm5 10.104.0.15 POST /createticket/submit.py - 443 - 10.104.0.15 HTTP/1.1 Mozilla/5.0+(Windows+NT+10.0;+Win64;+x64)+AppleWebKit/537.36+(KHTML,+like+Gecko)+Chrome/130.0.0.0+Safari/537.36 - REDACTED/.../partsrec-art.html REDACTED 200 0 0 1798 1108 9916
2024-10-25 15:25:18 W3SVC1 bchdm5 10.104.0.15 POST /createticket-test/submit.py - 443 - 10.104.0.15 HTTP/1.1 Mozilla/5.0+(Windows+NT+10.0;+Win64;+x64)+AppleWebKit/537.36+(KHTML,+like+Gecko)+Chrome/130.0.0.0+Safari/537.36 - REDACTED/.../partsrec-art.html REDACTED 200 0 0 1453 1139 7401
2024-10-25 15:26:51 W3SVC1 bchdm5 10.104.0.15 POST /createticket/submit.py - 443 - 10.104.0.15 HTTP/1.1 Mozilla/5.0+(Windows+NT+10.0;+Win64;+x64)+AppleWebKit/537.36+(KHTML,+like+Gecko)+Chrome/130.0.0.0+Safari/537.36 - REDACTED/.../partsrec-art.html REDACTED 200 0 0 1507 1114 7288
2024-10-25 15:32:23 W3SVC1 bchdm5 10.104.0.15 POST /createticket/submit.py - 443 - 10.105.54.144 HTTP/1.1 Mozilla/5.0+(Windows+NT+10.0;+Win64;+x64)+AppleWebKit/537.36+(KHTML,+like+Gecko)+Chrome/125.0.0.0+Safari/537.36 - http://REDACTED / REDACTED 200 0 0 1506 1147 78283
2024-10-25 15:39:09 W3SVC1 bchdm5 10.104.0.15 POST /createticket/submit.py - 443 - 10.105.53.136 HTTP/1.1 Mozilla/5.0+(Windows+NT+10.0;+Win64;+x64)+AppleWebKit/537.36+(KHTML,+like+Gecko)+Chrome/129.0.0.0+Safari/537.36 - http://REDACTED / REDACTED 200 0 0 1510 1139 70529
Hope this helps someone.
