Error: 20501, Severity: 16, Could not insertt into sysarticleupdates using sp_articlecolumn.
Error: 20503, Severity: 16, Invalid ‘%s’ value in ‘%s’. The publication is not enabled for ‘%s’ updatable subscriptions.
Error: 20504, Severity: 16, Immediate Updating Subscriptions: The xml values inserted/updated by Subscriber will be replicated as NULL to publisher.
Error: 20505, Severity: 16, Could not drop synchronous update stored procedure ‘%s’ in ‘%s’.

Error: 20506, Severity: 16, Source table ‘%s’ not found in ‘%s’.
Error: 20507, Severity: 16, Table ‘%s’ not found in ‘%s’.
Error: 20508, Severity: 11, Updatable subscriptions: The text, ntext, or image values inserted at the Subscriber will be NULL.
Error: 20509, Severity: 16, Updatable subscriptions: The text, ntext, or image values cannot be updated at the Subscriber.

Error: 20510, Severity: 16, Updateable Subscriptions: Cannot update identity columns.
Error: 20511, Severity: 16, Updateable Subscriptions: Cannot update timestamp columns.
Error: 20512, Severity: 16, Updateable Subscriptions: Rolling back transaction.
Error: 20513, Severity: 16, Database ‘%s’ does not contain any replication metadata for a row whose ROWGUIDCOL matches the value specified for the @rowguid parameter of sp_showrowreplicainfo. Verify that the value specified for @rowguid parameter is correct.
Error: 20514, Severity: 10, A rowcount validation request has been submitted to heterogeneous publisher %s for article %s of publication %s. Validation results will be posted to distribution history.
Error: 20515, Severity: 16, Updateable Subscriptions: Rows do not match between Publisher and Subscriber. Run the Distribution Agent to refresh rows at the Subscriber.
Error: 20516, Severity: 16, Updateable Subscriptions: Replicated data is not updatable.
Error: 20518, Severity: 16, Updateable Subscriptions: INSERT and DELETE operations are not supported unless published table has a timestamp column.
Error: 20519, Severity: 16, Updateable Subscriptions: INSERT operations on tables with identity or timestamp columns are not allowed unless a primary key is defined at the Subscriber.
Error: 20520, Severity: 16, Updateable Subscriptions: UPDATE operations on tables with identity or timestamp columns are not allowed unless a primary key is defined at the Subscriber.
Error: 20521, Severity: 16, sp_MSmark_proc_norepl: must be a member of the db_owner or sysadmin roles.

This is applicable on below versions of SQL Server

SQL Server 2005
SQL Server 2008 R2
SQL Server 2012
SQL Server 2014

Hope this was helpful.

Thanks,
SQLServerF1 Team
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