In Salesforce, some automations require the use of specific operators that only use picklist fields for their selections. As such, to use these automations, you must manually add "RB2B" as a Lead Source in your picklist values in your Salesforce instance.
How to Add "RB2B" to Lead Source and Account Source Picklists in Salesforce
Go to Setup
Click the gear icon in the top right corner and select Setup.
Modify Picklist Values for Lead Source
In the Quick Find search bar, type Object Manager and click it.
Scroll down and select Lead.
Click Fields & Relationships on the left panel.
Find and click on Lead Source.
Scroll to the Values section and click New.
Type RB2B and click Save.
Modify Picklist Values for Account Source
Go back to Object Manager and select Account.
Click Fields & Relationships and find Account Source.
Click on Account Source, then scroll down to the Values section.
Click New, type RB2B, and click Save.
Once you’ve added "RB2B" to these picklists, it will be available as an option in reports, filters, and lead/account management.
Alternative Approach for Lead Source (If You Need More Flexibility)
Since picklists don’t support Contains or Starts With, you can create a Formula Field that converts Lead Source into text:
Go to Setup > Object Manager > Account (or Lead).
Click Fields & Relationships > New Field.
Select Formula and set the return type to Text.
Use this formula:
TEXT(LeadSource)
Save the field and now you can filter using
Containsin reports and automation.