I have a phone that I have been able to contact via BOINC Manager and BOINCTUI for years, but since a few days it is impossible. I check all computers and devices via BOINCTUI every day. There has been no upgrades of BOINC Manager or BOINCTUI on the computers or BOINC for Android on the phone. The phone uses boinc_7.18.1.apk 2021-08-08 11:18 12M since that is the latest version that works on that phone. I have tried newer, but they were not possible to install. It is possible to ping the phone from the same computer that runs BOINC Manager and BOINCTUI. I have of course tried to restart the phone and BOINC restarts automatically, but it still cannot communicate with BOINC Manager and BOINCTUI. The phone still runs e.g. Einstein@home and WUProp@home and reports finished tasks.

Last month it did, according to WUProp@home:
Einstein@Home Binary Radio Pulsar Search (Arecibo,GBT) 348.72 h (100.00%)
Last week:
Einstein@Home Binary Radio Pulsar Search (Arecibo,GBT) 31.98 h (100.00%)

About the phone:
samsung GT-S6790N - SDK: 16 ABI: armeabi-v7a
ARM
ARMv7 Processor rev 9 (v7l) [Impl 0x41 Arch 7 Variant 0x2 Part 0xc09 Rev 9]
(1 processors)
Android
3.0.15-1379436 (Android 4.1.2)

It is the same problem to connect on other computers with BOINCTUI or BOINC Manager with Linux or Windows. Both the phone and the computers running BOINCTUI or BOINC Manager are on the same network and ping works. I have many other Android devices that can be contacted without problems. I have password on all Android devices.

---