My camera Tapo C510W was connected to my home assistant home automation and was working fine. And suddenly it didn't work anymore. It looks like you introduced a bug.

After resetting the user/pass a few time and trying to changes some settings I started to look into it in VLC and it seems it has a but in the RTSP server commands handling.

$ /Applications/VLC.app/Contents/MacOS/VLC -vvv rtsp://camera:camera@192.168.1.122:554/stream1
VLC media player 3.0.21 Vetinari (revision 3.0.21-0-gdd8bfdbabe)
Opening connection to 192.168.1.122, port 554...
...remote connection opened
Sending request: OPTIONS rtsp://192.168.1.122:554/stream1 RTSP/1.0
CSeq: 2
User-Agent: LibVLC/3.0.21 (LIVE555 Streaming Media v2016.11.28)

Received 152 new bytes of response data.
Received a complete OPTIONS response:
RTSP/1.0 200 OK
CSeq: 2
Date: Sun, Jun 23 2024 09:42:27 GMT
Public: OPTIONS, DESCRIBE, SETUP, TEARDOWN, PLAY, PAUSE, GET_PARAMETER, SET_PARAMETER

Sending request: DESCRIBE rtsp://192.168.1.122:554/stream1 RTSP/1.0
CSeq: 3
User-Agent: LibVLC/3.0.21 (LIVE555 Streaming Media v2016.11.28)
Accept: application/sdp

Received 220 new bytes of response data.
Received a complete DESCRIBE response:
RTSP/1.0 401 Unauthorized
CSeq: 3
Date: Sun, Jun 23 2024 09:42:27 GMT
WWW-Authenticate: Basic realm="TP-LINK IP-Camera"
WWW-Authenticate: Digest realm="TP-LINK IP-Camera", nonce="fd7f0e20ca06f9349e6e218b2eb617a0"

Resending...
Sending request: DESCRIBE rtsp://192.168.1.122:554/stream1 RTSP/1.0
CSeq: 4
Authorization: Digest username="camera", realm="TP-LINK IP-Camera", nonce="fd7f0e20ca06f9349e6e218b2eb617a0", uri="rtsp://192.168.1.122:554/stream1", response="e34c5553e7aa4d07b2fb41694ccef09b"
User-Agent: LibVLC/3.0.21 (LIVE555 Streaming Media v2016.11.28)
Accept: application/sdp

Received 576 new bytes of response data.
Received a complete DESCRIBE response:
RTSP/1.0 200 OK
CSeq: 4
Date: Sun, Jun 23 2024 09:42:27 GMT
Content-Base: rtsp://192.168.1.122:554/stream1/
Content-Type: application/sdp
Content-Length: 410

v=0
o=- 14665860 31787219 1 IN IP4 192.168.1.122
s=Session streamed by "TP-LINK RTSP Server"
t=0 0
m=video 0 RTP/AVP 96
c=IN IP4 0.0.0.0
b=AS:4096
a=range:npt=0-
a=control:track1
a=rtpmap:96 H264/90000
a=fmtp:96 packetization-mode=1; profile-level-id=640034; sprop-parameter-sets=J2QANK0AzoAkAKOmoCAgPgAAAwAOAAADAZBvIH0Au7//gUA=,KO48sA==
m=audio 0 RTP/AVP 8
a=rtpmap:8 PCMA/8000
a=control:track2

Sending request: SETUP rtsp://192.168.1.122:554/stream1/track1 RTSP/1.0
CSeq: 5
Authorization: Digest username="camera", realm="TP-LINK IP-Camera", nonce="fd7f0e20ca06f9349e6e218b2eb617a0", uri="rtsp://192.168.1.122:554/stream1/", response="3c2d0b4f30f697922cc4808b2b708adb"
User-Agent: LibVLC/3.0.21 (LIVE555 Streaming Media v2016.11.28)
Transport: RTP/AVP;unicast;client_port=56690-56691

Received 74 new bytes of response data.
Received a complete (unknown) response:
RTSP/1.0 400 Bad Request
CSeq: 4
Date: Sun, Jun 23 2024 09:42:27 GMT