i am constantly getting this error and i cannot sync with the blockchain:

2018-Jul-15 10:20:34.705696 WARNING Proof of work too weak for block 620009 (96e7b5a6d5e965a2a17d9f816ed1a6ea06869ec1e3f549084020e678acb15368)

Any help please?

Edit: I resolved the problem by updating the cli wallet to 0.6.3.