I have a retailer that is unable to completely connect to our Filezilla Server. We recently implemented a Filezilla Server with SSL certificate. All my other retailers are connecting to our server. When this retailer is unable to connect, it gives him a "425 Can't open data connection for transfer of "/""
The ports I have open for this server is the following: Listen on 21021 and 5990-5995 for Passive Mode.
I have asked that he have his IT department look at their firewall and make sure those ports are open for access. They sent back a screenshot of what looks like a connection analyzer and it says that it didn't receive a SYN/ACK from me.
I have used this account at offsite facilities and was able to successfully connect. I am open to suggestions, I'm not sure where else to look for answers.
Thanks