Please follow the below steps/recommendations for each specific issue

This site can’t be reached   

• Check whether the World Wide Web Publishing Service (W3SVC) is stopped. If so, start the service
• Validate that ports 443 and 80 are in a LISTENING state
• Verify whether the ports are blocked by Windows Firewall or any network firewall
• Check the WSFTPSVR site bindings in IIS and ensure they are correctly configured with the appropriate SSL certificate
• Confirm the URL and port are correct, and attempt to log in using:
  https://localhost/WSFTPSVR/Login.asp
• Clear the browser cache and verify that the issue is not caused by an unsupported browser.
• The Application pools must be in started condition. The Default WEB site hosting WSFTP Server Apps must be in started state.
• Click on Default Website-->edit bindings-->This section should have only Port 80 and 443 bindings. (Port 80 may be removed by BU if needed then WSFTP Server will only listen to Port 443)

Authentication Failed. Please check your username and Password 

• Ensure that valid administrator credentials are being used to log in to the Admin Console
• If multiple hosts are configured, attempt logging in using the host separator format, for example:
  username@hostname
• If you do not have access to the Admin account credentials, refer to the Article to regain access to the Admin Console
• If the issue persists, collect  the following Diagnostic logs and log a case with the Technical Support team
  

An error occurred on the server when processing the URL. Please contact the system administrator

• Please refer to the article here:  An error occurred while processing the URL
• If the issue persists, then follow the steps
  - Open IIS Manager, right-click on the WS_FTP_SERVER application pool, and select Advanced Settings. 
  - In the Advanced Settings dialog, expand Process Model and select the Identity field. Click the Browse (…) button. 
  - In the Application Pool Identity dialog, select Built-in account, choose NetworkService from the drop-down list, and click OK. 
  - Restart IIS by running the command prompt as an administrator
  - Check the Functionality 

HTTP Error 404. The requested resource is not found 

• Please refer to the article here:  Error 404 after logging in to WS_FTP Server Admin Console
• If the issue persists,   
  • Verify whether the WSFTPSVR application in IIS is configured with an incorrect physical path, which can prevent the Admin Console login page from loading
  • Confirm that the physical path is set to C:\Program Files (x86)\Progress\WS_FTP Server\WWWROOT\WSFTPSVR, or to the correct directory based on the installation
  • Open IIS Manager and navigate to the site where the Admin Console is hosted
  • Right‑click the WSFTPSVR application and select Manage Application → Advanced Settings
  • Update the Physical Path to the correct WSFTPSVR directory and save the changes
  • Restart IIS by running iisreset from an elevated command prompt to apply the changes. If the issue persists, 

401.2 - Unauthorized: Access is denied due to invalid credentials

• Please refer to the article here:  Unauthorized when attempting to browse to WS_FTP Server Manager

This site can’t be reached. The webpage at https://127.0.0.1/WSFTPSVR/default.asp might be temporarily down or it may have moved permanently to a new web address.
ERR_SSL_KEY_USAGE_INCOMPATIBLE

• Recent versions of Google Chrome (version 119.0.6045.160 and later) require the Digital Signature key usage to be present in the SSL certificate
• If the Digital Signature parameter is missing from a self‑signed certificate, an error may occur when attempting to log in to the WS_FTP Management Tool using the Chrome browser
• To resolve this issue, generate a trusted self‑signed certificate that includes the Digital Signature key usage
• Bind the newly created certificate to the appropriate site in IIS bindings
• Restart IIS and retry accessing the Management Tool using Google Chrome
• Please refer to the article here: How to apply an SSL certificate in IIS for use by WS_FTP Server

500 - Internal Server Error

• Please refer to the article here: How to fix the 500 - Internal Server Error

HTTP Error 500.19 - Internal Server Error-Cannot-add-duplicate-collection-entry-of-type-add-with-unique-key-attribute-name-set-to-X-Frame-Options" is being popped up while accessing WSFTP server manager/ Web transfer module after an upgrade/ migration. 

Check Default Web site in IIS-->HTTP response headers should be Blank. These Response headers are integrated with the WSFTP Server APPS so any entry under the default website will be inherited by the WSFTP Server apps and show duplicate.

HTTP Error 500.19 -Internal Server Error 

• Please refer to the article here: HTTP Error 500.19 accessing WSFTP server manager after upgrade/ migration