With respect to upgrade paths, 7.8.x → 7.10.x I know works as I’ve done that before, so if you can, you could try to install in multiple steps (7.10.x) being the latest LTS version:
for 7.10.x links
If this is not possible, then we need to look at the various log files that are available.
Generally these are:
suitecrm.log in your web root (or other custom location
/var/log/httpd/error.log or access.log
/var/log/php-fpm.log
I’ve given a number of default paths primarily relating to a centos distro. There may be other logs that can help, but start there and see what you can find out? Your operating system and version might be useful along with php/mysql version for checking against the compatibility matrix:
Are your versions still supported on the 7.11.x version?