Traceback (most recent call last):
  File "site-packages\requests\packages\urllib3\connection.py", line 135, in _new_conn
  File "site-packages\requests\packages\urllib3\util\connection.py", line 90, in create_connection
  File "site-packages\requests\packages\urllib3\util\connection.py", line 80, in create_connection
TimeoutError: [WinError 10060] The attempt to establish a connection was unsuccessful because the required response was not received from another computer in the required time, or an already established connection was disconnected due to an incorrect response from an already connected computer
During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "site-packages\requests\packages\urllib3\connectionpool.py", line 559, in urlopen
  File "site-packages\requests\packages\urllib3\connectionpool.py", line 345, in _make_request
  File "site-packages\requests\packages\urllib3\connectionpool.py", line 782, in _validate_conn
  File "site-packages\requests\packages\urllib3\connection.py", line 215, in connect
  File "site-packages\requests\packages\urllib3\connection.py", line 144, in _new_conn
requests.packages.urllib3.exceptions.NewConnectionError: <requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0x03900550>: Failed to establish a new connection: [WinError 10060] The attempt to establish a connection was unsuccessful because the required response was not received from another computer in the required time, or an already established connection was disconnected due to an incorrect response from an already connected computer
During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "site-packages\requests\adapters.py", line 370, in send
  File "site-packages\requests\packages\urllib3\connectionpool.py", line 609, in urlopen
  File "site-packages\requests\packages\urllib3\util\retry.py", line 271, in increment
requests.packages.urllib3.exceptions.MaxRetryError: HTTPSConnectionPool(host='api.exchangeratesapi.io', port=443): Max retries exceeded with url: /latest (Caused by NewConnectionError('<requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0x03900550>: Failed to establish a new connection: [WinError 10060] The attempt to establish a connection was unsuccessful because the required response was not received from another computer in the required time, or an already established connection was disconnected due to an incorrect response from an already connected computer
During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "main.py", line 22, in <module>
  File "src\downloadrates.py", line 7, in src.downloadrates.download
  File "site-packages\requests\api.py", line 69, in get
  File "site-packages\requests\api.py", line 50, in request
  File "site-packages\requests\sessions.py", line 468, in request
  File "site-packages\requests\sessions.py", line 576, in send
  File "site-packages\requests\adapters.py", line 423, in send
requests.exceptions.ConnectionError: HTTPSConnectionPool(host='api.exchangeratesapi.io', port=443): Max retries exceeded with url: /latest (Caused by NewConnectionError('<requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0x03900550>: Failed to establish a new connection: [WinError 10060] The attempt to establish a connection was unsuccessful because the required response was not received from another computer in the required time, or an already established connection was disconnected due to an incorrect response from an already connected computer
During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "main.py", line 27, in <module>
NameError: name 'self' is not defined

yeah my bad. That seemed to not bethe latest build.
I'm not sure if you will not be getting the error again as the original exception was derived from an error while trying to download the rates file, but at least the other errors were cleared.

error
An error prevented the application to download the latest rates
OK
Traceback (most recent call last):
  File "main.pyw", line 28, in <module>
  File "src\interface.py", line 16, in src.interface.currency_gui.__init__
  File "src\interface.py", line 28, in src.interface.currency_gui.initUI
  File "src\conversion.py", line 9, in src.conversion.listcurrencies
FileNotFoundError: [Errno 2] No such file or directory: 'rates.txt'

I'm not sure what niche this program is filling, seems more like a practice project to me.
I mean typing 5.00 CAD in USD into Google for instance, gets you the same result.
I could see this being useful for seniors who are scared of the internet/google though I guess.

Plus many currencies, including my country's, are not there, so my only use for it would be when converting US Dollars to Euros or inversely, something I could do on Google's builtin currency convertor. Anyway, congrats for releasing the app and keep up the good work.

does this program have source code available? or did you just upload the folder on github? the last time i checked, i just saw that there was 1 exe file, and no other text files, and i got an error. It seems like the error has been fixed based on the posts, i will take a look at it now and download it.