While sending mail using Apex_Mail.ADD_Attachment utility in Apex 20.2 version, ORA-29279: SMTP permanent error: 552 exceeds byte limit error is stored in a mail queue. The file size is approximately 1.5 MB size. File is stored in database and using the stored procedure, we are extracting the BLOB file, attaching and sending the mails. Please suggest how to increase the attachment file sizes.