FTP Connection Problems

I am having trouble FTPing from Adobe Lightroom Classic (v11.3.1) to my IONOS (1and1.com) server.

In particular, I have been FTPing web picture galleries from Lightroom Classic to my IONOS (1and1.com) server for years.  I never had any problems to speak of, and I have uploaded hundreds of web galleries containing thousands of pictures over the last few years.  The process was easy, quick, and painless.

Recently, I have encountered FTP connection problems with the IONOS server.  I blamed IONOS for the problem; however, their tech service wizards say there is nothing wrong on their end.

With IONOS tech services assistance, we checked to make sure my log-in credentials were correct, and they were.  The tech service reps say they had no problem logging-in using my credentials; however, I have problems trying to log-in (or FTP) when I use Lightroom Classic and Dreamweaver.

When I attempt to upload a Lightroom web gallery, I receive the following error note about 6 out of 10 tries: “FTP transfer failed with message ‘an unknown error occurred.’”  The other 4 FTP attempts may (or may not) be successful.

If I try to access the IONOS server via Dreamweaver (v21.2), I receive the following error message 4 out of 5 tries: “An FTP error occurred – cannot make connection to host.  Your login or password is incorrect.  Please check your connection information.”  Obviously, if my login information was incorrect, I would never be able to login to the host (but I can approximately 1 out of 5 times).

One of the IONOS tech service wizards also helped me download and set up FileZilla.  I am able to connect to the IONOS server most of the time on the first attempt (using the same exact login credentials that I use for Lightroom and Dreamweaver).  If I knew how to upload a Lightroom web picture gallery from FileZilla to the IONOS server, I would start doing that immediately.

Can anyone offer helpful words of wisdom?  Thank you.