Issues like that can be caused by the infamous "Error code: 1219". Check the console.log file in C:\ProgramData\Online Backup\logs.

If you see "Multiple connections to a server or shared resource by the same user, using more than one user name, are not allowed. Disconnect all previous connections to the server or shared resource and try again" message I suggest to check out this article: https://serverfault.com/questions/919337/how-to-clean-up-old-connections-before-mapping-a-new-drive

Thanks. Removed mapped drive and it connects.