Trying to backup any postgresql database but got this error, right after pressing backup button. I need to make back up in pgadmin. I have tried many variants pgadmin 3,4 - same error. Now i am on bigsql's pgdevops , but same error. Maybe something with linux roles, access rights? I am using linux mint 18.2
Here is the Error message: 
If i need some tricks with rights, where should it be done? I just starting ./pgc start pgdevops wehre should i check/set rights?