I can see the errors; probably the server needed to heat up on your side.
Seems like there is a problem with name resolution for the database servers, as there is no record for almost any of them on InfinityFree’s domain. It used to work before that because for name resolutions they used to use Byet’s DNS servers; can you try to use sql305.byetcluster.com as host instead and see if it works?
For any others having this issue: replace 305 with the database server number.
EDIT: If anyone else is having that issue, that is also explained in this outage topic: