When you have a Windows Server operating system installed or Windows 7, You might be facing  "Could not load TLS libraries" Error after FileZilla Server start up attempted.

Sometimes, Installing Windows Updates fixes this in full or you can follow the below steps -

Go to This Link & Download the suitable one for your Operating System -

For Win 7 32-Bit - http://www.microsoft.com/downloads/details.aspx?familyid=c79c41b0-fbfb-4d61-b5d8-cadbe184b9fc

For Win 7 64-Bit - http://www.microsoft.com/downloads/details.aspx?familyid=146ed6f7-b605-4270-8ec4-b9f0f284bb9e

For Win Server 2008 32-Bit - http://www.microsoft.com/downloads/details.aspx?familyid=16277ab2-c39d-4c61-bfce-3a1ed64aab02

For Win Server 2008 64-Bit - http://www.microsoft.com/downloads/details.aspx?familyid=755cab42-2ce6-499a-bb8e-e5f1c17ce8ad

For Win Server 2008 R2 - http://www.microsoft.com/downloads/details.aspx?familyid=c841c22c-3459-4c18-9bc9-53d76c375ab4

More Info here - https://support.microsoft.com/en-us/help/2533623/microsoft-security-advisory-insecure-library-loading-could-allow-remote-code-execution

Filezilla Official Error Discussion topic for this matter is here - https://forum.filezilla-project.org/viewtopic.php?t=39838

Note1: Your System required to be rebooted after the above knowledgebase/KB installation before you be able to start FileZilla Server Properly.
Note2: Make sure to add Firewall Rule/Allowing for your Filezilla Server.exe file in both "Inbound & Outbound" Rule. Filezilla Server.exe Is located here by default after an installation - C:\Program Files (x86)\FileZilla Server

Do not worry, let us know if you need further assistance.