I installed authy using the snap install authy command. When I try to open the application, I get the following error message:
/snap/authy/6/authy: error loading shared libraries: libX11.so.6: unable to open shared objects file: No such file or directory
Ubuntu 20.04.3 LTS
This forum poster seemed to have the same issue as you. There was quite a lot of process that they went through, but the thing that fixed it in the end was rebooting the machine.
Are you running parallel installs and does a reboot fix the issue for you?
Installing libx11-6:i386 worked for me:
sudo apt-get install libx11-6:i386
after that I experienced another error solved by installing libstdc++5:i386:
sudo apt-get install libstdc++5:i386