conda安装环境报错：Solving environment: failed with initial frozen solve.

(base) csd@amax:~$ conda install -c menpo opencv
Collecting package metadata (current_repodata.json): done
Solving environment: failed with initial frozen solve. Retrying with flexible solve.

我在menpo来源的opencv时，出现了这个问题。
1.尝试了https://blog.csdn.net/Erice_s/article/details/80156191 这位博主的方法失败
2.尝试了pip -i 链接失败
pip install -i https://pypi.tuna.tsinghua.edu.cn/simple tensorflow
3.尝试更新conda再输入失败
4.可能原因：直接下载的conda里面带的python是3.8，会不会是兼容性的问题？
最近在跑SiamFC，https://github.com/huanglianghua/siamfc-pytorch，出现的问题。
最后解决：
pip install menpo
pip install opencv-python