This issue is being investigated as bug LOS-1743 as of August 2018. If you encounter an issue contact support, so your organization can be connected to the issue for tracking.
Constituents can export their contacts from Yahoo and perform an import into the participant center using a CSV.
Export Contacts from Yahoo:
- Login to Yahoo on a PC.
- Choose Contacts
- Actions drop down > Export
- Select Yahoo CSV.
Import Contacts to Participant Center:
- Login to the Participant Center.
- Select the Email tab.
- Contacts > Import Contacts.
- Choose file based import > and select the file you downloaded from Yahoo.
- Click Next through the options and finish.