Choose the source type deliberately
MAC-ID uses a portal URL with the relevant device registration. XC uses a server/portal URL plus username and password. M3U uses a playlist file or address. These are distinct forms, not three names for a single text field.
Use the details supplied for the selected method. A long playlist URL can contain credentials, so do not put it into a public post or screenshot. If you have been given the wrong format for the intended source type, resolve that mismatch before repeatedly submitting the same value.
Test the source after it has connected
After the source loads, inspect categories, guide information and one actual playback task. A source can appear in the manager while a later media request still fails. Keep the exact stage in the diagnosis.
Application functions such as recording or multiple sources also depend on the installed version, storage arrangement, source support and account conditions. Do not infer all of those conditions from a panel or menu label.
Retain the right identifiers
For support, record the Formuler model, MYTVOnline generation, source type and error wording. Share private account/device identifiers only through the appropriate support route. The distinction between a device-registration issue and an XC password issue is useful; publishing either identifier is not necessary to explain it.