Duplicate Matching Rules are blocking Web-to-Lead submissions when the rule is set to Allow and Alert
Here is the error you might receive:
Error: Salesforce could not create this lead because of the reason listed below. For more information about this error or help with Web-to-Lead, please contact Customer Support.
Reason: You're creating a duplicate record. We recommend you use an existing record instead.
Note: There may also be instances where the records are not blocked and are allowed to be created even when the duplicate rule is met.
This usually happens when there are dirty records or several of the matches are in the recycle bin.
Please empty the recycle bin and have Salesforce Support run a Physical Delete job on the object.
000387310

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