cgminer solo mining "Pool 0 slow/down or URL or credentials invalid”

[MixPioneer]

I'm in trouble. Please help me. Thank you.
I have a Gridseed 5-chip GC3355
solo mining use the cgminer-3-7-2-gridseed-windows
The xxx.conf file  >>>
rpcallowip=127.0.0.1
A coin:rpcport=8333
B coin:rpcport=8332
The xxx.bat file   >>>
A coin:cgminer.exe --scrypt -o http://127.0.0.1:8333 -u a -p b --gridseed-options=baud=115200,freq=850,chips=5 --hotplug 5
B coin:cgminer.exe --scrypt -o http://127.0.0.1:8332 -u a -p b --gridseed-options=baud=115200,freq=850,chips=5 --hotplug 5
When solo A coin, the cgminer works fine.
But when it comes to solo B coin, it's an error “Pool 0 slow/down or URL or credentials invalid”

[MixPioneer]

I don't know what the problem is.
Because A coin is all right.
I need your help.
Thank you, guys.