ProSites crashing admin on activation

hi,
every time i activate ProSites i get locked out of admin.
the front end seems to work fine.
the first time it happened i got 'screenshot1' message.
the second time i got 'screenshot2' message.


it actually happened previously when i had "defender" and "humming bird" installed so i figured one or both were the problems since they are new and given the errors provided.
so i actually deleted the entire site and database and started all over with a clean install.
but now i get the same issue without "defender" and "humming bird" installed.
is ProSites php 7.0.3 compatible ?
i tried applying define('WP_MEMORY_LIMIT', '256M':wink:; but it did not help
i also tried without that line in wp-config and same problem.

support access granted if needed.
i am also shooting a ticket to SiteGround as well to tackle this from both ends.
your very kind assistance in this would be greatly appreciated.
kind regards.