Question: After renaming my heroku app from the heroku website, whenever I cd to its directory in a terminal and run any heroku command, I get `App not found`. Does anybody know of a way to remedy this?

Answer: 
The Answer by James Ward is also correct, alternatively try doing this:

1). open a terminal

2). Go to your\_app\_directory/.git/config

3). Once you open the config file then edit as follows:

Change

```
url = git@heroku.com:old_app_name.git

```

to

```
url = git@heroku.com:new_app_name.git

```

Obviously substituting your apps old name to its new name. Hope it helps
Also checkout this link [renaming from cli - heroku](http://devcenter.heroku.com/articles/renaming-apps)
There is another way, you can fix it by renaming the app to the original name via web.

To find out the old name use heroku command line: 

```
> heroku rename newname

```

which will spit out the old name. Use the old name to rename the app via web. You can check if renaming success by running 

```
> heroku info

```

Once done you can rename to the preferred name by using

```
> heroku rename preferredname

```