Can't install extensions through manager and sample data not showing up

[darknessxk]

Well as my title says my magento set-up is not working properly

Extension manager issue:

 

and my homepage/ sample data does not show nothing

 

someone can give me any light? ideas for solving this issue will be so useful tried reinstalling, changing php version (7.2 current) i am using nginx and mariadb, redis and vanish for cache.

is a vps hosted on namecheap with full root control

[theMageComp]

Hello @darknessxk 

We won't be able to see your screenshot until moderator approves.

But meanwhile I can guess,

Did you run upgrade, static reply, cache flush, indexing commands after installation?

php bin/magento setup:upgrade

php bin/magento setup:static-content:deploy

php bin/magento cache:clean

php bin/magento cache:flush

php bin/magento indexer:reindex