openSession(file.location = "http://nrnb.org/data/BasicDataVizDemo.cys") does not work

> openSession(file.location = "http://nrnb.org/data/BasicDataVizDemo.cys")
Opening http://nrnb.org/data/BasicDataVizDemo.cys...
RCy3::commandsPOST, HTTP Error Code: 500
 url=http://localhost:1234/v1/commands/session/open
 body={
 "url": "http://nrnb.org/data/BasicDataVizDemo.cys" 
}
Error in commandsPOST(paste0("session open ", type, "=\"", file.location,  : 
  Mark/Reset not supported.
> sessionInfo()
R version 3.6.1 (2019-07-05)
Platform: x86_64-apple-darwin15.6.0 (64-bit)
Running under: macOS Mojave 10.14.6

Matrix products: default
BLAS:   /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib
LAPACK: /Library/Frameworks/R.framework/Versions/3.6/Resources/lib/libRlapack.dylib

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] RCy3_2.5.6

loaded via a namespace (and not attached):
 [1] igraph_1.2.4.1      graph_1.63.0        Rcpp_1.0.2          knitr_1.24          magrittr_1.5        BiocGenerics_0.31.5
 [7] R6_2.4.0            stringr_1.4.0       httr_1.4.1          tools_3.6.1         parallel_3.6.1      xfun_0.9           
[13] R.oo_1.22.0         htmltools_0.3.6     yaml_2.2.0          digest_0.6.20       RJSONIO_1.3-1.2     BiocManager_1.30.4 
[19] base64enc_0.1-3     R.utils_2.9.0       curl_4.0            evaluate_0.14       rmarkdown_1.15      stringi_1.4.3      
[25] compiler_3.6.1      R.methodsS3_1.7.1   stats4_3.6.1        XML_3.98-1.20       jsonlite_1.6        pkgconfig_2.0.2

cytoscape / RCy3

openSession(file.location = "http://nrnb.org/data/BasicDataVizDemo.cys") does not work #68