No progress bar, no backup file saved, error sending to dropbox

I have used BackWPUp on multiple sites, with success. On one particular site I’m running into several issues that I have never encountered before.

Setup:
The plugin is set to backup files and database and send the file to Dropbox. Dropbox is authenticated. The site is on Cloudflare and using Cloudflare plugin. Disable SSL Verify mini-plugin is also installed. While trying to debug, I’ve tried sending to Dropbox and to Folder (neither work), and I’ve tried in CF development mode.

Issues:
1. When the job is started, the message ‘Job “Daily Backup” started.’ appears, but there is no indication that anything is happening. No error messages appear.

2. When “Log” link is clicked in BackWpUp Job list an empty window appears.

3. Log files DO appear in ‘WP-Content/Uploads/backwpup-*****-logs/’ and logs are sent by email eventually (30 – 60 minutes after job start).

4. No backup archive file is saved locally when the plugin is set to save to Folder to ‘WP-Content/Uploads/’; No files are sent to Dropbox when the plugin is set to send to Dropbox.

5. Logs indicate that the backup archive file is created:

[16-Sep-2015 16:49:43] Backup archive created.

but sending to Dropbox fails with this error:

[16-Sep-2015 16:49:56] ERROR: Dropbox API: (35) error:0D0890A1:asn1 encoding routines:ASN1_verify:unknown message digest algorithm

If anyone can help point me in the right direction, I would greatly appreciate it.

Thank you!

https://wordpress.org/plugins/backwpup/