The most likely cause here is either:
- One or more of your DFS map points point to folder targets that only support SMB v1 (File Director 4.x and above only support SMB 2/SMB 3)
A method of checking the available SMB version of a given file server is detailed in the following blog - https://www.ivanti.com/blog/performance-improvements-in-datanow-v4/
- Your file server(s) does not have a valid reverse DNS record (PTR record) that matches its A record - File Director 4.0+ has strict requirements for PTR records in order to support file servers that are behind NLB devices. Use NSLookup to confirm that the required PTR records are in place, and if not, add them. Verifying Your Basic DNS Configuration
Re TLS 1.0 - the experience between client and browser can be different - In Windows, the browser uses WinINET settings, and the client uses WinHTTP, which may have differences in support with TLS. by default Windows 7 WinHTTP does not support TLS1.1/1.2 and needs additional configuration. The setting in the admin console also applies to client connections.
I hope this helps