Marika.
Have you tried changing your internet source?...if you normally play through wi-fi....have you tried playing through mobile data instead to see if that changes anything?
Also have you tried completely shutting down your router?
Do you have the ability to change your router settings/firewall?
Are you running a firewall on your mobile device &/or your PC?....could there be settings in there you could change?
Also are you running any virus, malware, adware, ransomware, etc type of protection programs/apps on your mobile device &/or PC?..... could there be any settings in there you could change?
From my personal experiences I believe it could be a bandwidth, buffering &/or latency issue....why I say this is because...I recently bought a new phone..... I've been waiting for nearly a year for this phone to come on special.
I bought an Asus ROG Phone 3 Qualcomm® Snapdragon™ 865 Plus 5G Mobile Platform with UFS3.1 & 12GB RAM & 512GB storage. The 3.1 GHz high frequency CPU in the speed-binned Qualcomm Snapdragon 865 Plus Mobile Platform is accompanied by an overclocked Adreno 650 GPU that can deliver up to 10% better performance. Together with the fastest smartphone storage available (UFS3.1) & 12GB of RAM, you have the fastest Android phone ever built.
If I'm on a phone call at the same time of trying to claim an ad based reward....the ad screen will come up but the ad will not run....so I just have to either leave the ad screen there until I finish my phone call or I have cancel the ad which means that I will not get the reward & I will not have another chance to claim that reward.
I have had the ad screen just sitting there on my phone for at least 30mins while I'm on the phone call then as soon as I hang up the ad will automatically start up....if the ad doesn't automatically start click on the ad screen & it starts running then.
The only game I have installed is Diggys Adventure....I have only used 5% of my 512GB storage space.
Here are some interesting links in relation to routers & internet issues
https://www.novatech.co.uk/blog/best-router-settings-for-gaming/
https://www.highspeedinternet.com/resources/bandwidth-vs-latency-what-is-the-difference
https://www.pcmag.com/how-to/how-to-set-up-and-optimize-your-wireless-router-for-the-best-wi-fi-performance
https://www.google.com/amp/s/www.makeuseof.com/tag/gaming-router-tips-optimal-performance/amp/
https://www.google.com/amp/s/www.techspot.com/amp/article/2157-optimize-gaming-internet-connection/
https://www.google.com/amp/s/www.dnsstuff.com/latency-throughput-bandwidth/amp