michelrrr → created an issue.
you were absolutely right while talking about a problem with the DB ... Thanks !
The issue was not on the settings but on a table definition for the Collation format. I didn't saw that the import of the sql was crashing at one point => Unknown collation: 'utf8mb4_0900_ai_ci'
Solution : I just edited the sql file and fixed the name of the collation for that table and I could import it successfully.
Issue solved... and it was not linked to Drupal Core ;)
Thanks for your proposal, and yes, that was also my first idea... but it didn't changed since years.
To be sure, I did the install steps until then end and during the install process, I didn't got the screen to enter DB connection sctrings neither username-pwd. At the end of the install, I got a clean fresh DB emptied of my previous sql import => it means that the settings.php was the right one.
something else to check ?
Thanks #35 !!
My config was :
OVH
10.1.8 ALL FINE, no problem
10.2.x migration => HTTP/2 with net::err_http2_protocol_error
Solved by adding 'Header always unset Content-Length' in .htaccess of www
<IfModule mod_headers.c>
Header onsuccess unset X-Content-Type-Options
Header always set X-Content-Type-Options nosniff
Header always unset Content-Length
RequestHeader unset Proxy
</IfModule>