Oracle APEX - Invalid lob when calling to APEX Apex_mail.send

Question

I have a Oracle Database 18c Standard Edition 2 Release 18.0.0.0.0 server with Oracle apex 19 running on a Linux box.

I am testing send emails with templates build on Apex. If I run the below code I get a error

begin

  Apex_mail.send(p_application_id     => 100,
                 p_to                 => '[email protected]',
                 p_from               => '[email protected]',
                 p_template_static_id => 'TEST',
                 p_placeholders       => '{"count":1}');
end; 

ORA-06502: PL/SQL: error : invalid LOB locator specified: ORA-22275 numérico o de valor
ORA-06512: en "SYS.DBMS_LOB", línea 727
ORA-06512: en "APEX_190100.WWV_FLOW_MAIL", línea 776
ORA-06512: en "APEX_190100.WWV_FLOW_MAIL", línea 849
ORA-06512: en "APEX_190100.WWV_FLOW_MAIL", línea 873
ORA-06512: en "APEX_190100.WWV_FLOW_MAIL_API", línea 88
ORA-06512: en línea 3

I've tested same code in other Oracle server without problem.

If I call to the overloaded function of APEX_mai.send as bellow, it work fine.

begin
  
  apex_mail.send(p_to   => '[email protected]',
                 p_from => '[email protected],
                 p_body => 'Main email text goes here',
                 p_subj => 'APEX_MAIL - Plain Text message');
  Apex_Mail.push_queue;
end;

Note: Application 100 and template "TEST" exists in my apex workspace

My question, what is the problem in my code when I use template?

I have tried sending an empty placeholder, but I get the same result

Answer 1

I found the problem, For some strange reason, the "text plain" template should not be empty, I added a "."(yes, a simple dot) in the template with plain text and it started working.