Never mind

A friend sent me an email apologizing for not replying to the last email I sent her last week.

Is it correct to say ' Never mind replying that email' 'Never mind forgetting to reply'

What am I supposed to say?.

Thanks a lot
Nathalie

[MrPedantic]

Hello Nathalie

You can say:

1. Don't worry about not replying to that email, it doesn't matter!
2. Never mind, it wasn't important!

(I expect other members will have other suggestions.)

I wouldn't say –

3. Don't worry about forgetting to reply.

– because a reference to someone else's forgetfulness might seem rude.

MrP