- Due to Antivirus interference.
- Windows update is maybe blocking the TLS 1.1 support.
- Event Logging value is missing in Windows Registry.
- Your device files are maybe corrupted. Thus causing the error.
SChannel Error 36887 (Fatal Alert 40, 42, 49) : How to Fix?
Though there is no specific fix for this issue, you have to try all the solutions that are mentioned below.
Adding the EventLogging Registry key
Maintaining an event logging registry key is important to fix the Channel error 36887 data error issue. So follow these simple steps to fix the issue easily.
Step 1) Open up your Registry Editor by simply typing Registry in the windows search bar, or you can press the Windows key + R to open up the Run Dialog box, and there you type “Regedit” to open up the registry editor.
Step 2) Now, on the left pane of the window, navigate to the following directory.
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\SecurityProviders\SCHANNEL

Step 3) After you have located the above directory. On the right pane of the window. Right-click on the empty space and select the NEW option. Select Dword and enter the Value name as EventLogging.
Step 4) Set the Value data to 1 and click on the OK button to confirm it.
Step 5) Locate the following directory.
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
And right-click on the fipsalgorithmpolicy, set the value data to 1.
Now, you must reboot your device and do the task that was showing you the 36887 error.
Removing Windows updates patches
There are countless windows updates that are faulty in nature. So, upon installing, they cause more harm then fixing itself. So if the Error SChannel 36887 issue is arising due to a recent windows update, then you have to delete that update immediately. Follow this guide down below to remove any unnecessary windows update.
Step 1) Open up the Run Dialog box by pressing the Windows key + R, type rstrui, and click on the OK button to open up the system restore.
Step 2) Now, on the system restore window, click on the Next button, and check on the option, Show more restore points. Select the restore pony before windows update and click on the Next button again.

Step 3) Click on Finish to complete it. Your device will reboot and reset to its previous state however, if you must go to windows security and update settings and configure not to install KB3161606 package on your system.
Run the DISM and SFC scans on your system
The command prompt is none important and essential tool for windows. With its help, you can fix easy and complex problems with just a few commands. With commons prompt, you can easily fix the SChannel Error 36887 issue on your PC.
Step 1) Type cmd in the windows search bar, right-click on the command prompt app, and run it as an administrator.
Step 2) Type the command mentioned below and press enter.
sfc/scannow

Step 3) Reboot your computer and keep sure that you are connected to the internet then do the DISM scan by typing the following command and press enter.
DISM /Online /Cleanup-Image / ScanHealth

If there is any corrupted file, it will detect it, and you will have to remove those files to fix the error.
Disable the TLS option used by Windows
Step 1) Open up the Run Dialog box and type inetcpl.cpl , click OK to open up the Internet Options.
Step 2) The Internet options window will appear, o to the Advanced tab, and scroll down to the security section, navigate to the option Use TLS 1.0, Use TLS 1.1 and Use TLS 1.2. Uncheck all the TLS related options. Now click on the Apply button to confirm.

Step 3) Click on the OK button to confirm and close it, restart your device, and do the task that you were doing. Check if the error code 36887 has resolved.
Uninstalling the Antivirus
Antivirus can hinder a lot of fo services on Windows PC. And because fo such hindering, you might be seeing the Fatal Error 40, 42, 49 issues on SChannel. But do not worry, either disable your Antivirus or uninstall it completely.
Step 1) Open up the Windows settings, go to Apps, and click on the Programs & features option.
Step 2) Now, you just have to locate the Antivirus software that is installed on your system and right-click on it.
Step 3) Select the Uninstall option and uninstall the Antivirus.

Restart your computer and check if the error is still showing up.
Conclusion
The new SChannel Error 36887 (Fatal Alert 40, 42, 49) is a new error message faced my multiple users worldwide. However, it is an easy Error to solve as compared to others. Please follow all the troubleshooting steps carefully in order to solve the problem.