Not able to see my lambda functions

This issue you're experiencing with Lambda functions not being visible and encountering an "UnknownError" is not uncommon and can have several potential causes:

1. Region Check: First, ensure you're in the correct AWS region where your Lambda functions were originally created. Lambda functions are region-specific, so if you're in a different region, they won't be visible.

2. Temporary Block: There's a possibility that your account might have experienced a temporary block due to a suspected malicious access attempt. This can sometimes cause functions to become temporarily inaccessible.

3. IAM Permissions: Even though you're using the root user, it's worth double-checking that your account has the necessary IAM permissions to access Lambda functions. Insufficient permissions can lead to "UnknownError" messages.

4. Service Health: Check the AWS Service Health Dashboard to see if there are any ongoing issues or outages with Lambda in your region.

5. Browser/Device: Try accessing your Lambda functions from a different browser or device to rule out any local issues.

6. Recent Activity: If your Lambda functions haven't been invoked for an extended period (e.g., over 3 months), they might not appear in certain Lambda monitoring tools, although they should still be visible in the main console.

If the issue persists after checking these points, it's recommended to contact AWS Support. You can open a case under "Account and billing" which can be done free of charge. They can investigate any account-specific issues that might be causing this problem.

In the meantime, since you mentioned being able to access other AWS services, you might want to check your CloudTrail event history to see if there are any clues about recent activities or permission changes related to your Lambda functions.
Sources
My Previously created Functions not Visible and getting UnknownError | AWS re:Post
UnknownError Lambda | AWS re:Post
(LAMBDA) UnknownError in AWS Console | AWS re:Post
Not able to access Lambda functions Tab | AWS re:Post

Hello.

I have experienced the same error in the past, but I was able to resolve it by opening a case with AWS Support under "Account and billing."
I would recommend contacting AWS support.
Inquiries under "Account and billing" can be made free of charge.
https://repost.aws/ja/questions/QUPpcS3wYaR12wHug50trqQQ/unknown-error-in-lambda?sc_ichannel=ha&sc_ilang=en&sc_isite=repost&sc_iplace=hp&sc_icontent=QUPpcS3wYaR12wHug50trqQQ&sc_ipos=5