Comment 7 for bug 1408107

Unfortunately, gvfs can't control the timeouts that libsmbclient uses. I recommend filing a bug at https://bugzilla.samba.org/ or asking a question on the mailing list: https://lists.samba.org/mailman/listinfo/samba

Alternatively, you could try poke about on the router and see what is happening, e.g. if the server crashes or something.