Is it possible to use the default mozilla-sync server? Topic is solved

[ambivalence]

…or is these browser use different versions of sync protocol? If it's possible, what is the server's address?

[adesh]

No, it's not possible. Pale Moon uses Sync 1.1, Mozilla Sync 1.5; both are incompatible.

[Moonchild]

Also, don't be fooled by the minor version number difference. "Sync 1.1" is Weave based. "Sync 1.5" is Mozilla's "Firefox Accounts" based which is a totally different thing.