Please ask these in the correct thread (viewtopic.php?f=73&t=220613&sid=d95dab9 ... c6c67efd60
) instead of opening a new one.
Make sure you've followed instructions in the FAQ on how to install gapps:
Q: How to install Google apps?
1. Download MindTheGapps-8.1.0-arm-XXXXXXXX_XXXXXX.zip and save it to your device’s internal storage or use an external USB drive
2. Boot to TWRP recovery (see FAQ)
3. Install MindTheGapps-8.1.0-arm-XXXXXXXX_XXXXXX.zip from your selected storage
4. Wipe->Factory reset!
5. Boot out of recovery (see FAQ)
MindTheGapps package is recommended with LineageOS 15.1 instead of Open GApps. You also need to perform a factory reset.