iOS keeps enabling 'Protect Mail Activity'

If this is your personal device then you can update your device with the current iOS

Know how to...

• Update Over-the-Air (OTA) —> Update your iPhone or iPad - Apple Support (IN)
• Update using iTunes/Finder —> Update your iPhone, iPad, or iPod touch - Apple Support (IN)

If this is your corporate iPhone, it is important to reach out to the system administrator of your corporate. They will be able to assist you with any issues or concerns related to your device.

However, if it is your personal device, there are a few things to consider. Firstly, check if you have any profiles installed by your corporate, organization, enterprise, or school management. These profiles are typically used to manage certain settings or restrictions on your device.

If you do have a profile installed, and you no longer wish to keep it, you can follow the steps provided by Apple to remove configuration profiles on your iPhone. By doing so, you will eliminate the profile and its associated settings from your device. Install or remove configuration profiles on iPhone - Apple ...

In case you need further guidance or encounter any difficulties during the process, it is recommended to contact the system administrator of the organization that provided the profile to you. They will be able to assist you in removing the profile or addressing any concerns you may have.

Updating iOS on your iPhone should typically not alter the fundamental functionality of the device. It's possible that there were underlying issues before this update, which you might not have been aware of previously or might not have noticed.

In general, iOS updates are designed to enhance the user experience, improve security, and fix bugs, rather than introducing major disruptions to core features. The reported issue of the screen flickering and displaying a white screen after an update is likely caused by factors that are not explicitly mentioned in your post.

iOS updates primarily focus on improving system performance, introducing new features, fixing bugs, and enhancing security. They are designed to preserve your personal data, settings, and information intact.

During an iOS update, your device's operating system is upgraded, but your personal data, such as contacts, photos, messages, and other information, should remain unchanged. However, it's always a good practice to perform a backup of your device before any major update to ensure that your data is safely stored.

It's important to note that while an iOS update itself should not alter personal details, it's possible that certain features or settings may be adjusted or improved with the update. In such cases, you may need to review and adjust specific settings to match your preferences after the update.

Always make sure to read and understand the update details provided by Apple before proceeding with an iOS update, and follow best practices such as backing up your device to minimize any potential risks or complications.

If the issues you mentioned are indeed caused by iOS, it's likely that numerous users who have upgraded to iOS 16.6.1 are experiencing similar problems. However, in order for the community on this forum to provide helpful responses, it would be beneficial for you to specify the nature of the issue you are encountering. Without this information, it may be difficult for others to address your concern effectively.

With the limited information that you have provided, It is hard to even guess the problems faced by you. 

You may get faster and better responses to your query by --> Writing an effective Apple Support Commun… - Apple ...

Please re-post with detail so that someone else can help.