Problem with mail app after updating to iOS 26

You may have enabled Authenticator for Yahoo --> Generate and manage third-party app passwords | Yahoo Help

An app-specific password is a unique password generated by a service provider, such as Apple, Yahoo, or Google, that allows you to grant access to a specific application or service without using your main account password. It is typically used when you want to use a third-party app (For Yahoo, iOS is a third-party) or service that requires access to your account but doesn't support the usual authentication methods, like two-factor authentication.

Here's how an app-specific password differs from your email password:

1. Purpose: Your email password is used to access your email account directly through email clients or webmail interfaces. It allows you to read, send, and manage your emails. On the other hand, an app-specific password is used to grant access to a specific app or service that requires access to your account, but doesn't support standard authentication methods.
2. Security: App-specific passwords are designed to enhance security by limiting access to specific applications or services. They are generated for individual apps or services, and if compromised, they can be revoked without affecting your main account password. In contrast, your email password is the primary key to access your email account, and if it's compromised, an attacker could gain unauthorized access to your emails and potentially other account-related information.
3. Management: App-specific passwords are typically managed separately from your main account password. Service providers like Apple or Google allow you to generate, view, and manage app-specific passwords through their account management interfaces. These passwords can be created, revoked, or regenerated as needed. Your email password, on the other hand, is managed directly through your email service's account settings.
4. Limitations: App-specific passwords have limitations to ensure security. They are usually one-time-use passwords, meaning that once you enter them in an app or service, you may not need to remember them or enter them again. Some service providers also impose restrictions on the number of app-specific passwords you can generate or the duration of their validity. Email passwords, on the other hand, remain consistent until you decide to change them.

It's important to note that not all service providers offer app-specific passwords, and their availability and implementation may vary across different platforms and applications. If you need to grant access to a third-party app or service and are unsure about the authentication requirements, it's recommended to check the documentation or support resources provided by the service provider for specific instructions.

It's not always the iOS update's fault!  Many things can cause phone problems.  If you tell people you think it's an iOS update, it might make it harder to fix or find a solution for the real issue.

Remember, the right question often leads to the solution!

Was/Is your device Jailbroken? If that's the situation, please be informed that attributing the issues to iOS updates may not be accurate.

iOS updates aim to enhance user experience, boost security, and fix bugs rather than disrupt core features. The majority of the issues after updates might stem from underlying, unmentioned factors. Updates won't typically alter personal data but may refine settings or features. Backup before major updates for safety. Review Apple's update details and backup advice for a smooth process.

Kindly consider checking your settings and addressing any device issues before attributing the issue to external factors. This could be a pure coincidence that the iOS update affected the iPhone functions.

Before initiating a standard iOS update, it's advisable to create a backup. Have you completed this step? If yes, proceed with the restoration from the backup.

See what each update does: OS — iOS 26, About iOS 18 Updates, About iOS 17 Updates, About iOS 16 Updates, About iOS 15 Updates, About iOS 14 Updates, About iOS 13 Updates, About iOS 12 Updates, and so on...