Samsung
Add an Email Account (POP3/IMAP) auf Samsung
Samsung phones do not ship with a dedicated mail app for every provider. Instead, the Gmail app works as a collective inbox that can hold Gmail, T-Online, Web.de, GMX and most other addresses side by side.
To link an external provider, Samsung needs to know which protocol to use. Exchange covers business accounts managed by a company server. Personal (IMAP) keeps mail synced across all your devices, since messages stay on the provider's server. Personal (POP3) downloads mail directly to the phone and often removes it from the server afterward.
To add the account, go to Tap on Settings ➔ Tap on Accounts and backup ➔ Tap on Manage accounts ➔ Tap on Add account, then pick Exchange, Personal (IMAP) or Personal (POP3) depending on your provider's recommendation.
If the account was already added once but stopped syncing, check the sync toggle for that account under the same accounts menu instead of adding it again. Some providers also require an app-specific password once two-factor authentication is active, which is a separate setting on the provider's own website.