Rokus can only connect to one Netflix account at a time, but then, most of us only have one Netflix account. But we CAN have multiple PROFILES within that one account.
Early Netflix did not support multiple profiles - all settings/history/etc just related to the account as a whole. The early Netflix apps for Roku at the time ran these single-profile apps on early Rokus just fine.
Netflix itself added multiple profiles eventually and created updated versions of their Roku app to support it, but they would only run on newer Roku models that had greater capabilities. To their credit, however, they kept the old versions in the system so older Rokus like your LT would continue to work in single profile mode.
Roku Streaming Stick +, 3810X, Ser YH0059427035, wifi - Samsung UN55ES6100
Roku Streaming Stick, 3600X, Ser 5S56D8240827, wifi - JVC EM37T