Any idea what it means?
If I close message I can connect generally on the second attempt, that tells me the key etc is correct.
I have space on servers, I have internet bandwidth 500 mbits+, Vmix Program is 27.0.0.91, PC is same one used fine for couple of years, nothing changed
IBM support says it's Vmix software

Error Message

FFMPEG1.Exited
Streaming
[rtmp @ 05e95980] Cannot open connection tcp://23123891.fme.ustream.tv:1935
rtmp://23123891.fme.ustream.tv/ustreamVideo/23123891/.....: I/O error

libavcodec 57.106.101 / 57.106.101
libavformat 57. 82.101 / 57. 82.101
libavdevice 57. 8.101 / 57. 8.101
libavfilter 6.105.100 / 6.105.100
libswscale 4. 7.103 / 4. 7.103
libswresample 2. 8.100 / 2. 8.100
libpostproc 54. 6.100 / 54. 6.100
Guessed Channel Layout for Input Stream #0.1 : stereo
Input #0, dshow, from 'video=vMix Video YV12:audio=vMix Audio':
Duration: N/A, start: 79763.966000, bitrate: 1536 kb/s
Stream #0:0: Video: rawvideo (YV12 / 0x32315659), yuv420p, 1920x1080, 50 fps, 50 tbr, 10000k tbn, 10000k tbc
Stream #0:1: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
[dshow @ 02b17bc0] real-time buffer [vMix Video YV12] [video input] too full or near too full (63% of size: 128000000 [rtbufsize parameter])! frame dropped!
[dshow @ 02b17bc0] real-time buffer [vMix Video YV12] [video input] too full or near too full (65% of size: 128000000 [rtbufsize parameter])! frame dropped!
[dshow @ 02b17bc0] real-time buffer [vMix Video YV12] [video input] too full or near too full (68% of size: 128000000 [rtbufsize parameter])! frame dropped!
[dshow @ 02b17bc0] real-time buffer [vMix Video YV12] [video input] too full or near too full (70% of size: 128000000 [rtbufsize parameter])! frame dropped!
[tcp @ 05e95e00] Failed to resolve hostname 23123891.fme.ustream.tv: Temporary failure in name resolution
[rtmp @ 05e95980] Cannot open connection tcp://23123891.fme.ustream.tv:1935
rtmp://23123891.fme.ustream.tv/ustreamVideo/23123891/: I/O error
[dshow @ 02b17bc0] real-time buffer [vMix Video YV12] [video input] too full or near too full (72% of size: 128000000 [rtbufsize parameter])! frame dropped!

Any idea what it means, if I close message I can connect generally on the second attempt