LWT installation failed using OPAM

Question

LWT installation failed using OPAM on Ubuntu

Server Information -

Distributor ID: Ubuntu, Description: Ubuntu 18.04.4, LTS Release: 18.04,
Codename: bionic

Steps I followed -

opam list -a         # List the available packages
opam install lwt     # Install LWT
opam update          # Update the package list
...
opam upgrade         # Upgrade the installed packages to their latest version

Error I got -

=-=- Error report -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

The following actions were aborted
  ∗  install lwt       4.1.0
  ∗  install ocamlfind 1.8.0
The following actions failed
  ∗  install conf-m4 1
No changes have been performed

I even tried opam depext conf-m4.1 but didn't help.

Answer 1

After following these -

opam depext conf-m4.1

sudo opam install lwt

the problem is solved - but sudo is not recommended.