Unable to convert suggested difficulty error displayed by miningcore
Hello, 

I run solo(for fun) bitcoin pool by using miningcore which is great with fronted in place now,  but yesterday i got unusual issue while renting 1P from miningrigrentals.com -attached as a picture

Had no issue before with any rigs rented from miningrigrentals

Any ideae why it happened or how to fix, please?
![sketch-1534843820912](https://user-images.githubusercontent.com/39295831/44393732-c6164c80-a535-11e8-8870-1d463420cc61.png)
