Hi there! Sorry to hear about the connection issues. By server do you mean a Realm, a locally saved world, or perhaps the alpha version of private Bedrock servers? ^AG
Understood, a third party SMP server, thanks for clarifying. You can try disabling running services that are taking up bandwidth, rebooting your router, or perhaps contacting your ISP. If those don't work, contacting the server owners may help, too. ^AG