Hi @Roksund,
On top of the network test that @Charles suggested, do you have any warnings on the web interface System page about throttling (companion computer too hot) or under-voltage (insufficient power)?
If you have an under-voltage warning, are you using our 5V6A BEC (provided with our ROVs since October 2018), or do you have an older ROV with a 5V3A BEC instead?
More generally, can you confirm which companion software version you’re using? It should be specified on the System page, in the header bar and also in the “Companion Software Status” section. If you’re not on the latest one (0.0.28) there should be an update button in companion section 