Zend certified PHP/Magento developer

Migration from Magento 1.6.2.0 to Magento 2.4.3 Undefined index: in Migration/Step/Eav/Integrity/ClassMap.php on line 111

I’m using the data-migration-tool.

Steps to reproduce:

  1. A fresh install of Magento 2.4.3-p1
  2. A DB of Magento 1.6.2.0 in a remote server with remote access working
  3. Data-migration-tool 2.4.3 instaled
  4. Created a module with migration settings
  5. migrate:settings command is all fine
  6. migrate:data stops with an error

[2021-11-02 17:00:21][INFO][mode: data][stage: integrity check][step: EAV Step]: started
100% [============================] Remaining Time: < 1 sec
In ErrorHandler.php line 61:

Notice: Undefined index: in >/var/www/vhosts/blablabla.com/httpdocs/blablabla/testing/vendor/magento/data-migration-tool/src/Migration/Step/Eav/Integrity/ClassMap.php on line 111

I can’t tell if it already left the “EAV Step” and started the next step “Customer Attributes Step”, or if it’s still “EAV Step”, but the error line is inside the function checkClassMapping(), so I’m not even sure of what to do now.

Can’t find anything about this error in particular, and everything else about the EAV Step errors, doesn’t to be what I’m having.

Help?

Thanks