Hi marc-antoine07,
Let's resolve your issue by completing the steps listed here: Add an email account to your iPhone, iPad, or iPod touch - Apple Support to add the email account back to your iPhone. The steps are also listed below.
"How to set up your email account automatically
If you use an email provider like iCloud, Google, or Yahoo, Mail can automatically set up your email account with just your email address and password. Here's how:
- Go to Settings > Mail, then tap Accounts.
- Tap Add Account, then select your email provider.
- Enter your email address and password.
- If you see Next, tap Next and wait for Mail to verify your account.
- If you see Save, tap Save.
If you don't see your email provider, tap Other to add your account manually."
Best regards.