Cannot authenticate custom connector in a flow

[JulieKotatkova]

We deployed the TALXIS Document Connector to PCT18031 Test environment through pipeline a the custom connector was approved in the tenant by system admin.

There is flow that is using it on the environment and since it was returning 401 Unauthorized error message both in the flow and in the connector itself and resaving the connector and creating new connection did not work, I deleted the connection, redeployed the connector solution and created a new connection. After this, resaving the connector and changing the connection in the connection referrence, it returned a new error message in the flow run:

{ "status": 404, "source": "[https://europe-002.token.azure-apim.net:443/tokens/europe-002/talxis-5ftalxis-5fconnectors-5fdocuments-5fdb8f0b18aed0d3be/c7cacc10409d491d9e60bb426b364469/exchange"](https://europe-002.token.azure-apim.net/tokens/europe-002/talxis-5ftalxis-5fconnectors-5fdocuments-5fdb8f0b18aed0d3be/c7cacc10409d491d9e60bb426b364469/exchange%22), "message": "Error from token exchange: The connection (europe-002/talxis-5ftalxis-5fconnectors-5fdocuments-5fdb8f0b18aed0d3be/c7cacc10409d491d9e60bb426b364469) is not found. Please create new connection and change your application to use the new connection." }

So I created a new connection and changed it the connection refference once again, but it returned 401 Unauthorized again.

I repeated all the steps again, also tried it all from the second account we have and since then I am getting only 401 error in the flow - even though in the custom connector test mode I get a regular 500 so it should be authorized.

Any suggestions?