Yes, clearly. Insufficient RAM.
In your settings, you have 50% RAM set. Even if you used 100% RAM those phones would barely run.
Your phones have insufficient spec to run Rosetta, but they might have enough to run WCG. Give that project a try.

Yes I changed the settings to 80% RAM. But you're right. It's not that good ;)
I'm crunching for WCG already but wanted to crunch for F@h too - this is why I was asking.
Thanks for your answer Sid Clery!

Question: Is there a Phone/Tablet with more than 4 or even 6 GB of RAM?

I used to have a Samsung Galaxy S4 too. Then an S6, now an S8, which has 4Gb ram and allows me to run 4 of its 8 cores on Rosetta with room to spare

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