Why am I getting an error of UPGRADE FAILED: timed out waiting for the condition after creating a user and using it for my alpine image?

Question

The error I'm getting:

Error: UPGRADE FAILED: timed out waiting for the condition

Here is my dockerfile:

FROM nginx:1.15.1-alpine
COPY nginx/default.conf /etc/nginx/conf.d
RUN rm -rf /usr/share/nginx/html/*
COPY dist /usr/share/nginx/html
RUN addgroup -S appgroup && adduser -D -S appuser -G appgroup
USER appuser
EXPOSE 80
CMD ["nginx", "-g", "daemon off;"]

I started getting this error when I implemented this in my deployment.yaml:

 securityContext:
            capabilities:
              drop:
                - ALL
            allowPrivilegeEscalation: false
            runAsNonRoot: true
            runAsUser: 1212

I tried to follow this other answer: How do I add a user when I'm using Alpine as a base image?

With the code provided am I not giving a user for the image?