I can't access server

[nanciv]

Hello there. I have been struggling to connect to my ftp server for my webhosting company since March. Coronavirus and a complete shut down of my business sector hasn't meant I have had to make use of the 6 websites I administer up now. I am now at a point when I do need to update pages on the websites and still having problems. I have contacted: Norton to see if my antivirus was blocking Filezilla; Microsoft so if it was something to do with updates to Windows 10 and also my webhosts TSOhost who maintain the problem is not at their end. I have even updated my router thinking that it was a fault with the old one as it wasn't secure anymore. This literally happened from one week to another; one day it connected fine the next it didn't.
When I enter the logon details, which have been confirmed correct, I simple get this string of messages;
Status: Selected port usually in use by a different protocol.
Status: Resolving address of jakarta.footholds.net
Status: Connecting to 87.247.245.150:21...
Status: Connection established, initializing TLS...
Error: GnuTLS error -15: An unexpected TLS packet was received.
Status: Connection attempt failed with "ECONNABORTED - Connection aborted".
Error: Could not connect to server
Status: Waiting to retry...
Status: Resolving address of jakarta.footholds.net
Status: Connecting to 87.247.245.150:21...
Status: Connection established, initializing TLS...
Error: GnuTLS error -15: An unexpected TLS packet was received.
Status: Connection attempt failed with "ECONNABORTED - Connection aborted".
Error: Could not connect to server

[botg]

Status: Selected port usually in use by a different protocol.

Are you by chance trying to use implicit FTP over TLS over the port reserved for explicit FTP over TLS?

[nanciv]

Thanks for that and responding so promptly.
My colleague who is working on one of the websites from a different IP address using a Mac and and also using Filezilla to transfer files. The error message he is getting is:
Status: Resolving address of ftp.sussexartscollective.com
Status: Connecting to 87.247.245.150:21...
Status: Connection established, waiting for welcome message...
Status: Initializing TLS...
Status: Verifying certificate...
Status: TLS connection established.
Status: Logged in
Status: Retrieving directory listing...
Command: PWD
Response: 257 "/" is your current location
Command: TYPE I
Response: 200 TYPE is now 8-bit binary
Command: PASV
Response: 227 Entering Passive Mode (87,247,245,150,242,95)
Command: MLSD
Error: Connection timed out after 20 seconds of inactivity
Error: Failed to retrieve directory listing

Although we both are familiar with the terms you mention neither of us have the technical knowhow to apply the information to solve the problem. What do we have to do to correct the problem?

[botg]

The second log shows a different problem. Most likely the server is behind a firewall that isn't configured correctly for FTP over TLS. Please contact your server administrator or server hosting provider to have the server's firewall fixed.