Hi,
You mention that you're running both WRF and WRF-solar. Does this problem occur when you only run WRF (without WRF-solar)? If so, can you attach your namelist.input files for both simulations, as well as all of the wrf output and error files (e.g., rsl.error.*). If there are multiple error/out files, please package them together in a single *.TAR file. Thanks!