akonadi nor running after migration from kubuntu 18.04 to 19.10

[Daniel MOYNE]

could you please tell me how to fix this bug:

Mysql running but akonadi does not start and shows the following error 
message: Can't connect to local MySQL server through socket 
'/run/user/1000/akonadi/default/mysql.socket' (2)

I had to use thunderbird to send this message as kmail no more works.

Thank you

Daniel MOYNE