Please refer to the following steps to enable TLS 1.2 on Windows Server 2012.
1. At first, go to start and open the registry editor. Go to Start and Run. In the Run, type regedit and click on the OK button.
2. Back up the registry file. Click on File and then on Export. Select your location to save the registry file. It is always recommended to have the backup File of your registry file so that in case of an issue, you can import the File to make it as it was earlier.
3. Now, browse to the following registry key.
4. Right-click on the Protocols folder, select New, then Key using the dropdown. It will create a new folder and rename this folder to TLS 1.2.
5. Right-click on key TLS 1.2 and add two new keys Inside it and rename the two new keys as below.
6. Right-click on the Client key, select New, select DWORD (32-bit) Value from the dropdown, and rename the DWORD to DisabledByDefault.
7. Right-click on DisabledByDefault and select Modify from the dropdown, and make sure the Value data field is set to 0 and the Base is Hexadecimal. Then, click on the OK button.
8. Let's create another DWORD for the Client key as you did in Step 7 and rename the second DWORD to Enabled.
9. Right-click on Enabled, select Modify option from the dropdown and ensure the Value data field is set to 1 and the Base is Hexadecimal. Then, click on the OK button.
10. For the Server key, repeat steps 7 to 9 (create two DWORDs, DisabledByDefault and Enabled, and their values Inside the Server key).
11. Finally, Reboot the server, and TLS 1.2 is now enabled on your server.