OSX Mail - Impossible to see the mail

Hello everyone,

I have this problem.

When I restarted my computer I opened Mail OSX and the list of all my emails from the various mailboxes disappeared. I can see the bar on the left but I can no longer see the emails.

After a few minutes it invites me to exit and rebuild the database with the appropriate function but obviously when I restart I can't.

If I wait I get the second message where it tells me that if I close and restart mail, the index will be rebuilt.

But this doesn't happen.

Can you help me?

For your information, the OSX version is Mojave 10.14.6