cannot modifyheader headers already sent

[Maria Claudia]

Zen-cart 1.3.8
template classic
polish Beta - polish language as default
english
clones of table as table1 for modules/shipping
and for language
While instaling table1 on the Admin I received following message:

Warning: Cannot modify header information - headers already sent by (output started at /home/mysite/public_html/pl/zc3/includes/modules/shipping/table1.php:2) in /home/mysite/public_html/pl/zc3/admin/includes/functions/general.php on line 21



Sorry but I have no knowledge of php and this info cannot help me any further.


(This is a new cart I am trying to build)
thanks

[Ajeh]

Could you check the file, on the server, to see if you have space(s) or blank lines before the starting <?php code in that file?

https://www.zen-cart.com/tutorials/index.php?article=87

[Maria Claudia]

No, i'm afraid neither blank spaces or blank lines at the beginning of the clone.

[Ajeh]

Did you try to check the table1.php file that you have to ensure no space(s) and blank line(s) and then just reload the table1.php file to the server to see if this corrects the problem ...

[Maria Claudia]

I have more than one shipping module, I deleted table1 and all remaining ones were working. I than cloned again table1 and it is now working well. I suspect something went wrong in transfering this particular file. Thank you for your suggestion I would never thought just one file out of three would be corrupted.
Thanks a lot for your quick answer!