The error when windows launch without network and then open browser

[Yumingyuan]

Describe the bug If open browser when windows open up without network, and then connect to network and open Portal will report can not connect to the blockchain network, retry and will become normal.

To Reproduce (REQUIRED) Steps to reproduce the behavior, libraries used with version number, and/or any setup information to easily reproduce:

1. Open browser with out network
2. Click Portal icon
3. Portal will connect to blockchain network slowly
4. See error, retry it and become normal

Expected behavior Have some feature to handle this error.

Screenshots If we open browser without network, after connect to network and open portal will show this, very slow After a short of period, will tell you to retry After retry, the connection between portal and blockchain is ok

If applicable, add screenshots to help explain your problem.

Browser details (please complete the following information):

• OS: Windows
• Browser Chrome Version 79.0.3904.108 (Official Build) (64-bit)
• ConfluxPortal Version 0.3.5

Additional context (Error Messages, etc.) Add any other context about the problem here.

[Yumingyuan]

用中文说大致就是：如果我启动windows时，电脑网络没连接上，且浏览器自动启动或手动启动，之后让电脑联网，并启动Portal，会出现连接区块链网络（速度很慢），转了一会之后会出现连接失败，点击重试可连接成功。大概这么个问题。