There is a problem with exactly UDP output from encoder - it have a big spikes and non stable bitrate, also if you choose CBR output option it produces a complete shitty CBR ! Not good for DVB or any other data processing after transcoding. But you can use this transcoder (I think) for HLS, or other type HTTP streaming (segmental downloads).
WEB password works fine ! Try some simple login/passwd like ABC/abc - it should work.
ACL also works fine.
Tesla P4 is GEN6 NVENC card and is good if you stream video cameras or gaming from your PC
For TV channels and excellent quality you need Tesla T4 which is GEN7 NVENC and much better efficiency/quality !
The cards like Quadro RTX 3000-8000 and GeForce RTX 20xx-30xx - are all GEN7 NVENC encoders.