Template consumes too many server resources

Hi, I have a problem with the template. It consumes a lot of server resources and generates a 503 error.
My server tech support informed me that the template has an error.

The problem is not the plugins because I have disabled all of them and the problem persists.

I did another test and it was to activate all the plugins and change the template to “twenty twenty” and then everything works correctly without consuming resources on the server.

Can you help me find out what the problem is?

Thank you very much Elise. I will wait for your answer soon.
regards,
Maria

Thank you very much for the reply.
To reproduce the error, you must enter the wordpress back office and enter to any post to edit it. While editing a post you can open the website and browse it, especially the blog.
You will see that there is then a 503 error. This happens when have many open windows at the same time, or when many people browse the web at the same time.

The error reported by the server is the following:
[28-Jan-2021 17:03:36 UTC] PHP Warning: Use of undefined constant valid – assumed ‘valid’ (this will throw an Error in a future version of PHP) in / home / ohmykefir / public_html / wp-content /themes/woodmart/inc/classes/License.php on line 9

But also the theme is generating other php notices.

Please I need help inmediately.

You can see the php errors via: file manager -> public_html -> error_log.

Yes, you can change to another theme.

Thanks

You’re right. Now that you have disabled some plugins I see that the error does not occur.
Apparently the error comes from some plugin. How can I know which of all the plugins is causing the error?
Thanks you very much