Clear Books Apps hanging on 'Loading Bank Acconts'

My Clear Books App suddenly stopped working on my iPhone 6+. Never had a problem and was working flawless until recently when it started to keep hanging at the 'Loading Bank Accounts' stage. The loading circle keeps rotating but never completes and launches the App until it simply just shuts down the App without ever completing the loading bank accounts. It just returns back to the iPhone main screen. When trying to launch Clear Books again, the above just repeats. Apps authenticates followed by loading a couple of modules and then just keeps hanging on 'Loading Bank Accounts' for several minutes followed by closing down again and returning to iPhone main screen.

Perhaps the following helps to identify the possible cause for this. The difference between the Apps working without problems and now not working at all and not launching are the following changes:

1.) Added a second Organisation - 2.) Added two (Contra) Bank accounts for use of offsetting supplier bills with customer invoices. Before 7 bank accounts - Now 9 Bank accounts - 3.) Imported 3 csv bank statements for 3 of 9 bank accounts - 2 csv files not explained yet (0% completed) and 1 csv 39% explained so far.

The 3 yet to complete csv files have: 1 x 125 entries, 1 x 582 entries (both 0% completed) and 1 x 597 entries (39%) completed.

4.) Added 3 additional users to one of the organisations and 4 additional users to the second organisation

I have tried to delete the Apps, removed form phone, downloaded again and installed again to no avail. Apps keeps hanging at 'Loading Bank Accounts' stage, never completes loading followed by Apps closing and returning back to iPhone main screen.

Any ideas anyone?

Thanks

Ralph