# CDS API not working **URL:** \ **Category:** API\ **Tags:** api, cds\ **Created:** [12 August 2025 10:03 UTC](https://forum.ecmwf.int/t/cds-api-not-working/14010 "2025-08-12T10:03:59Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Mriganka\_Biswas](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/m/53a042/32.png) [@Mriganka\_Biswas](https://forum.ecmwf.int/u/Mriganka_Biswas)\ **Post date:** [12 August 2025 10:03 UTC](https://forum.ecmwf.int/t/cds-api-not-working/14010/1 "2025-08-12T10:03:59Z")
I am trying to download ‘cams-global-atmospheric-composition-forecasts‘ dataset using CDS API. However I am getting the following error ”” requests.exceptions.HTTPError: 404 Client Error: Not Found for url: [https://cds.climate.copernicus.eu/api/retrieve/v1/processes/cams-global-atmospheric-composition-forecasts](https://cds.climate.copernicus.eu/api/retrieve/v1/processes/cams-global-atmospheric-composition-forecasts) process not found dataset cams-global-atmospheric-composition-forecasts not found ““ Is CDS API connection down currently? Also is there any limit on much much data can be downloaded using single script using CDS API? ---
**Author:** ![Michela](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/m/898d66/32.png) [@Michela](https://forum.ecmwf.int/u/Michela)\ **Post date:** [12 August 2025 10:49 UTC](https://forum.ecmwf.int/t/cds-api-not-working/14010/2 "2025-08-12T10:49:58Z")
Hi, please copy the right URL from the following page: > **[CDSAPI setup](https://ads.atmosphere.copernicus.eu/how-to-api)** Thanks ---
**Author:** ![gael\_kermarrec1](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/g/7ea924/32.png) [@gael\_kermarrec1](https://forum.ecmwf.int/u/gael_kermarrec1)\ **Post date:** [12 August 2025 16:45 UTC](https://forum.ecmwf.int/t/cds-api-not-working/14010/3 "2025-08-12T16:45:23Z")
Hi, did it solve your problem? I have followed it exactly but the basic exemple still give me the folowing Traceback (most recent call last): File “/usr/lib/python3.12/idlelib/run.py”, line 580, in runcode exec(code, self.locals) File “/home/kermarrec/test3.py”, line 3, in client = cdsapi.Client() ^^^^^^^^^^^^^^^ File “/usr/lib/python3/dist-packages/cdsapi/api.py”, line 337, in **init** assert len(self.session.auth) == 2, ( ^^^^^^^^^^^^^^^^^^^^^^^^^^^ AssertionError: The cdsapi key provided is not the correct format, please ensure it conforms to: user::apikey I can download from the store without any problem. Thanks for any support ---
**Author:** ![Kevin\_Marsh](https://forum.ecmwf.int/user_avatar/forum.ecmwf.int/kevin_marsh/32/368_2.png) [@Kevin\_Marsh](https://forum.ecmwf.int/u/Kevin_Marsh)\ **Post date:** [14 August 2025 08:39 UTC](https://forum.ecmwf.int/t/cds-api-not-working/14010/4 "2025-08-14T08:39:29Z")
Are you using the latest version of the CDS API? ---
**Author:** ![jiang\_jun](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/j/46a35a/32.png) [@jiang\_jun](https://forum.ecmwf.int/u/jiang_jun)\ **Post date:** [26 August 2025 07:54 UTC](https://forum.ecmwf.int/t/cds-api-not-working/14010/5 "2025-08-26T07:54:05Z")
i copy the code from the dataset download form. **i run into the same error. i visit the** [https://cds.climate.copernicus.eu/api/retrieve/v1/processes](https://cds.climate.copernicus.eu/api/retrieve/v1/processes/cams-global-atmospheric-composition-forecasts) the ‘cams-global-atmospheric-composition-forecasts‘ dataset is not list in the requests ---
**Author:** ![Michela](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/m/898d66/32.png) [@Michela](https://forum.ecmwf.int/u/Michela)\ **Post date:** [26 August 2025 15:40 UTC](https://forum.ecmwf.int/t/cds-api-not-working/14010/6 "2025-08-26T15:40:09Z")
Hi, you need to use the right URL from the ADS in your cdsapirc file. Please see the following page: > **[CDSAPI setup](https://ads.atmosphere.copernicus.eu/how-to-api)** Thanks ---
**Author:** ![yu\_bing](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/y/8edcca/32.png) [@yu\_bing](https://forum.ecmwf.int/u/yu_bing)\ **Post date:** [27 April 2026 21:18 UTC](https://forum.ecmwf.int/t/cds-api-not-working/14010/7 "2026-04-27T21:18:32Z")
hello,i copied the right url.but still error. like this, requests.exceptions.HTTPError: 404 Client Error: Not Found for url: [https://ads.atmosphere.copernicus.eu/api/retrieve/v1/processes/s2s-reforecasts](https://ads.atmosphere.copernicus.eu/api/retrieve/v1/processes/s2s-reforecasts) process not found dataset s2s-reforecasts not found ---
**Author:** ![Kevin\_Marsh](https://forum.ecmwf.int/user_avatar/forum.ecmwf.int/kevin_marsh/32/368_2.png) [@Kevin\_Marsh](https://forum.ecmwf.int/u/Kevin_Marsh)\ **Post date:** [28 April 2026 13:18 UTC](https://forum.ecmwf.int/t/cds-api-not-working/14010/8 "2026-04-28T13:18:49Z")
Hi, you need to use the correct URL for the Data Store which has the data. In this case the data are on the ECDS, see: > **[CDSAPI setup](https://ecds.ecmwf.int/how-to-api)** for the correct details to use ---
**Author:** ![yu\_bing](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/y/8edcca/32.png) [@yu\_bing](https://forum.ecmwf.int/u/yu_bing)\ **Post date:** [30 April 2026 08:49 UTC](https://forum.ecmwf.int/t/cds-api-not-working/14010/9 "2026-04-30T08:49:34Z")
Oh, thank you very much for your help！