Try installing R from CRAN

.travis.yml

@@ -2,8 +2,6 @@ language: r
 dist: bionic
 cache: packages
 warnings_are_errors: true
-R:
-  - 4.4
 addons:
   apt:
     sources:
@@ -14,6 +12,10 @@ addons:
 #       - g++-7
 #       - python-pandas
 before_install:
+  - sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E298A3A825C0D65DFD57CBB651716619E084DAB9
+  - sudo add-apt-repository "deb https://cloud.r-project.org/bin/linux/ubuntu $(lsb_release -cs)-cran40/"
+  - sudo apt update
+  - sudo apt install r-base
   - pip3 install pandas
   - sudo $(which R) CMD javareconf
 #   - sudo $(which R) CMD javareconf