To connect, the client must understand the configuration supplied by the subscription. What matters is compatibility between the specific client and server settings, rather than the number of protocols in an app menu.
Incy and Happ support VLESS configurations. This does not mean that every setting in a third-party guide suits your subscription. Use the supplied parameters and change them manually only with clear instructions.
What the main terms mean
Protocol. The rules for communication between client and server. Selecting a different menu item does not switch the server itself to a new protocol.
Configuration. The settings for a specific connection: address, port and other values. An error in any of them can prevent a connection.
Subscription. A way to retrieve and update a set of configurations. Adding one server and importing a subscription are different actions, even when both use links.
Why importing the whole link is better
Transferring long values manually increases the risk of missing a character or mixing up fields. Importing transfers the settings in their intended format without assembling the connection yourself.
If the app reports an invalid format, check that you copied the connection details rather than your account page address. Do not paste explanatory message text with the link or send it to public online converters.
Import and connection errors differ
If the profile has not appeared in the list, investigate the link format and completeness, app version and subscription retrieval. The client is not yet ready for server selection at this stage.
If the profile appears but will not connect, check internet access and record the client message. An invalid-link error and a selected server timing out should be described separately: the same action need not fix both.