I/o timeout to dropbox

When trying to copy to Dropbox, I get these errors after some long minutes:

2018/03/17 22:38:38 ERROR : Attempt 1/3 failed with 1 errors
2018/03/17 22:41:58 ERROR : : error reading destination directory: Post https://api.dropboxapi.com/2/files/list_folder: dial tcp: lookup api.dropboxapi.com on 8.8.8.8:53: read udp 148.251.31.102:46325->8.8.8.8:53: i/o timeout
2018/03/17 22:41:58 ERROR : Attempt 2/3 failed with 1 errors
2018/03/17 22:45:18 ERROR : : error reading destination directory: Post https://api.dropboxapi.com/2/files/list_folder: dial tcp: lookup api.dropboxapi.com on 8.8.8.8:53: read udp 148.251.31.102:42156->8.8.8.8:53: i/o timeout
2018/03/17 22:45:18 ERROR : Attempt 3/3 failed with 1 errors

Where do I have to look to identify what is going wrong?

Any help is very welcome and appreciated

It looks like name resolution isn’t working properly for your machine.

Try

ping api.dropboxapi.com

does that work?