I’ve been running Piwik/Matomo on self host for years now.
Today, I’ve noticed I could not connect to Matomo server as I get the error message:
Cannot connect to the database:
SQLSTATE[HY000]  No such file or directory
I could not remember changing any thing on the server side, then I remembered I changed PHP Version. I switched back to PHP 5.6: I could log into Matomo. Then I switched to PHP 7.3, and I still could log into Matomo.
I don’t know what went wrong but I just thought I could share in case some one get stuck as well.