I use Google Maps (e.g. Google Satellite) as a basemap but after a few round of zooming in and out, the map would disappear. I have tried using maps from both OpenLayers and QuickMapServices (as the former seems to give problems to more people). QuickMapServices' maps were slightly better but the problem persists. I've checked that the CRS for the map layer and other layers match so don't think it's something to do with that.
Once the problem strikes, there seems to be nothing I can do. If I delete and add the map again, it will still not show. I can't even add other maps such as Bing Satellite. However, if I start a new project, the maps could work as per normal for the new project. This means that I have to abandon the whole project and start on a new one, and transfer whatever I've done to the new one. However, it happens so frequently that transferring is not viable.
Not sure if this will be useful but the version I'm using is QGIS 2.18 for mac.
I'm very new to QGIS.