Can't connect to FTP Server since switching to a Pixel 8 Pro

I have been using the app "FTP Server" for many years. Recently I have become unable to connect to it, since switching from a Pixel 6 Pro to a Pixel 8 Pro. I always get a "connection refused" error. I have tried connecting with Telnet, and get the same response. I can ping the phone without issue. I also tried the "primitive FTPd" app from Play/F-Droid. FTP Server app: https://play.google.com/store/apps/details?id=com.theolivetree.ftpserver primitive FTPd: https://play.google.com/store/apps/details?id=org.primftpd Is something different about networking on the Pixel 8? Or in Android 14? Edit: For reasons unknown, the next day, without rebooting the phone or anything like that, both "FTP Server" and "primitive FTPd" have started working. Perhaps it was a temporary issue, perhaps something else. I will report back if I make any progress on determining what circumstances cause this.