If CrewWeb seems slow, the problem is most likely the internet connection or the company’s CWA servers.
The CrewWeb app takes about 0.1% of the time. The other 99.9% is the internet and CWA server response.
Cellular data will be slower than a good Wi-Fi connection, but still should be fairly fast. Hotel and airport Wi-Fi can be slow; cellular data might be better. The aircraft Wi-Fi is the worst.
The company’s CWA servers might be part of the problem, especially if there are many crew members trying to access CWA at the same time.
In any case, the CrewWeb app is unlikely to be the cause of the problem. You can always try some of the basic troubleshooting, though, to see if it will improve the speed.
See also: internet connection.