error getting tracks from albums

[snippsat]

heiner55 is right you should always use +,which replace space.
Example with f-string(3.6),which make building string nicer.
lower() and join() with +,should work for most search word.

import requests

api_key = "b088cbedecd40b35dd89e90f55227ac2"
artists_search = 'the rolling stone'
artists_search = '+'.join(artists_search.lower().split())
artists_response = requests.get(f'http://ws.audioscrobbler.com/2.0/?method=artist.getinfo&artist={artists_search}&api_key={api_key}&format=json')
try:
    print(artists_response.json()['artist']['url'])
except KeyError:
    print('Artists not found')

Output:
https://www.last.fm/music/+noredirect/The+Rolling+Stone

If search for Bruno Mars same as over,and take out url used see that + is used.

Output:
https://www.last.fm/music/Bruno+Mars