You might come across at the time of launching the QB company file in multi-user mode. In addition to this, the same error may display when the company file you are trying to open, has been saved on another system. QuickBooks H303 error displays that the system needs additional configuration. You may look into the following causes to resolve the error manually.
What may lead to QuickBooks Error H303?
You first need to understand the root causes behind the issue and then try to fix it by taking the assistance of this post.
When the firewall blocks the communication related to the company file.
Due to an improper network connection of the PC.
Facing issues while acquiring the company files due to the files are hosted by the server.
Because of incorrect settings of hosting configuration.