Server Resource Packs no longer seem to work

In server.properties I have

resource-pack=https\://www.dropbox.com/s/a59ox9zcg47ee2i/resources.zip?dl\=1

resource-pack-sha1=A17985EAC50E5EE7F812F711E31E97749ED8B825

When launching the sever, there is no error saying the sha-1 does not match the file. In the client, the user has set Server Resource Packs to Prompt. Upon entering the server, the client does not get prompted to download a server resource pack, nor does a resource pack get downloaded. When the client has Server Resource Packs set to Enabled, the client does not download the resource pack.

Using the exact same server.properties in a 1.15.2 server functions correctly.