Update documentation error and Issue with SMTP under SSL

seems to me that the documentation for update InvoicePlane is wrong

Wrong because I cannot see space where put URL in index.php on a already installed version of Softacoulous.
I followed the guide, replaced all files except files indicated, than in index.php was not present the place where set the URL however I was able to point the browser to https://domain.ext/invoiceplane/setup and an error page that required to rename a ipconfig file and put again all database info… IP URL address… but all database info was present in a folder into database file…

I think guide is wrong or update process of InvoicePlane is very complicated. I was not able to do by following your guide.

I want ask about an SMTP problem
I transfered all my webspace to a new VPS and seems email from myaddress@subdomain.domain.ext fail with message SMTP Error: The following recipients failed: […] emporary local problem - please try later […] Temporary local problem - please try later

SMTP is valid… if I use the main domain myaddress@domain.ext mail is sent.

How I can see why the error occupr? Where or how to have some log? Where to look?

I have the last version 1.5.0

You are using the wrong guide. You have to use the guide for version 1.5 and not a previous version: