Hi @Alexandru Stamate ,
As we are mainly responsible for general issue of Microsoft Teams, your question which is involved in development is not supported by us. It recommends you ask in Teams developer forum. You will get the most qualified pool of respondents, and other partners who read the forums regularly can either share their knowledge or learn from your interaction.
The following link shows the steps how to build Microsoft Teams Custom Connector with Login Apps for your reference:
https://devkimchi.com/2019/08/28/two-ways-building-ms-teams-custom-connector-with-logic-apps/
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