Nick here from Shopify.
When you say the following:
How do you connect to the wholesalers ???
Do you mean connecting/downloading any of the Wholesale feature apps from the Shopify App Store or something else?
If so, are you having trouble downloading the apps to your store where it is showing an error message?
Shopify also has a wholesale sales channel, but that is only available if you are on the Shopify Plus plan. Maybe that could be why you're having trouble connecting to it if you were trying to add the sales channel?
If you could let me know which you're trying to connect to the wholesalers it would be a huge help in troubleshooting this. Looking forward to hearing from you.
All the best, Nick
That seems very strange. Can I ask which Wholesale app you downloaded exactly?
Just to be sure, once you downloaded the app, did you check the "App Section" of your admin to see if it appears there also?